Clean up CacheManager et al.

**UPDATE**

I have removed the special handling for `StorageLevel.MEMORY_*_SER` for now, because it introduces a potential performance regression. With the latest changes, this PR should include mainly style (code readability) fixes. The only functionality change is the update in `MemoryStore#putBytes` to actually return updated blocks, though this is a minor bug fix.

Now this is mainly a precursor to another PR (once again).

---------
*Old comment*

The deserialized version of a partition may occupy much more space than the serialized version. Therefore, if a partition is to be cached with `StorageLevel.MEMORY_*_SER`, we don't need to fully unroll it into an `ArrayBuffer`, but instead we can unroll it into a potentially much smaller `ByteBuffer`. This may save us from OOMs in this case.

Author: Andrew Or <andrewor14@gmail.com>

Closes #1083 from andrewor14/unroll-them-partitions and squashes the following commits:

7048aa0 [Andrew Or] Merge branch 'master' of github.com:apache/spark into unroll-them-partitions
3d9a366 [Andrew Or] Minor change for readability
d12b95f [Andrew Or] Remove unused imports (minor)
a4c387b [Andrew Or] Merge branch 'master' of github.com:apache/spark into unroll-them-partitions
cf5f565 [Andrew Or] Remove special handling for MEM_*_SER
0091ec0 [Andrew Or] Address review feedback
44ef282 [Andrew Or] Actually return updated blocks in putBytes
2941c89 [Andrew Or] Clean up BlockStore (minor)
a8f181d [Andrew Or] Add special handling for StorageLevel.MEMORY_*_SER
Move ScriptTransformation into the appropriate place.

Author: Reynold Xin <rxin@apache.org>

Closes #1162 from rxin/script and squashes the following commits:

2c836b9 [Reynold Xin] Move ScriptTransformation into the appropriate place.
[SQL] Use hive.SessionState, not the thread local SessionState

Note that this is simply mimicing lookupRelation(). I do not have a concrete notion of why this solution is necessarily right-er than SessionState.get, but SessionState.get is returning null, which is bad.

Author: Aaron Davidson <aaron@databricks.com>

Closes #1148 from aarondav/createtable and squashes the following commits:

37c3e7c [Aaron Davidson] [SQL] Use hive.SessionState, not the thread local SessionState
SPARK-1902 Silence stacktrace from logs when doing port failover to port n+1

Before:

```
14/06/08 23:58:23 WARN AbstractLifeCycle: FAILED SelectChannelConnector@0.0.0.0:4040: java.net.BindException: Address already in use
java.net.BindException: Address already in use
	at sun.nio.ch.Net.bind0(Native Method)
	at sun.nio.ch.Net.bind(Net.java:444)
	at sun.nio.ch.Net.bind(Net.java:436)
	at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:214)
	at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74)
	at org.eclipse.jetty.server.nio.SelectChannelConnector.open(SelectChannelConnector.java:187)
	at org.eclipse.jetty.server.AbstractConnector.doStart(AbstractConnector.java:316)
	at org.eclipse.jetty.server.nio.SelectChannelConnector.doStart(SelectChannelConnector.java:265)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
	at org.eclipse.jetty.server.Server.doStart(Server.java:293)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
	at org.apache.spark.ui.JettyUtils$$anonfun$1.apply$mcV$sp(JettyUtils.scala:192)
	at org.apache.spark.ui.JettyUtils$$anonfun$1.apply(JettyUtils.scala:192)
	at org.apache.spark.ui.JettyUtils$$anonfun$1.apply(JettyUtils.scala:192)
	at scala.util.Try$.apply(Try.scala:161)
	at org.apache.spark.ui.JettyUtils$.connect$1(JettyUtils.scala:191)
	at org.apache.spark.ui.JettyUtils$.startJettyServer(JettyUtils.scala:205)
	at org.apache.spark.ui.WebUI.bind(WebUI.scala:99)
	at org.apache.spark.SparkContext.<init>(SparkContext.scala:223)
	at org.apache.spark.repl.SparkILoop.createSparkContext(SparkILoop.scala:957)
	at $line3.$read$$iwC$$iwC.<init>(<console>:8)
	at $line3.$read$$iwC.<init>(<console>:14)
	at $line3.$read.<init>(<console>:16)
	at $line3.$read$.<init>(<console>:20)
	at $line3.$read$.<clinit>(<console>)
	at $line3.$eval$.<init>(<console>:7)
	at $line3.$eval$.<clinit>(<console>)
	at $line3.$eval.$print(<console>)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.apache.spark.repl.SparkIMain$ReadEvalPrint.call(SparkIMain.scala:788)
	at org.apache.spark.repl.SparkIMain$Request.loadAndRun(SparkIMain.scala:1056)
	at org.apache.spark.repl.SparkIMain.loadAndRunReq$1(SparkIMain.scala:614)
	at org.apache.spark.repl.SparkIMain.interpret(SparkIMain.scala:645)
	at org.apache.spark.repl.SparkIMain.interpret(SparkIMain.scala:609)
	at org.apache.spark.repl.SparkILoop.reallyInterpret$1(SparkILoop.scala:796)
	at org.apache.spark.repl.SparkILoop.interpretStartingWith(SparkILoop.scala:841)
	at org.apache.spark.repl.SparkILoop.command(SparkILoop.scala:753)
	at org.apache.spark.repl.SparkILoopInit$$anonfun$initializeSpark$1.apply(SparkILoopInit.scala:121)
	at org.apache.spark.repl.SparkILoopInit$$anonfun$initializeSpark$1.apply(SparkILoopInit.scala:120)
	at org.apache.spark.repl.SparkIMain.beQuietDuring(SparkIMain.scala:263)
	at org.apache.spark.repl.SparkILoopInit$class.initializeSpark(SparkILoopInit.scala:120)
	at org.apache.spark.repl.SparkILoop.initializeSpark(SparkILoop.scala:56)
	at org.apache.spark.repl.SparkILoop$$anonfun$process$1$$anonfun$apply$mcZ$sp$5.apply$mcV$sp(SparkILoop.scala:913)
	at org.apache.spark.repl.SparkILoopInit$class.runThunks(SparkILoopInit.scala:142)
	at org.apache.spark.repl.SparkILoop.runThunks(SparkILoop.scala:56)
	at org.apache.spark.repl.SparkILoopInit$class.postInitialization(SparkILoopInit.scala:104)
	at org.apache.spark.repl.SparkILoop.postInitialization(SparkILoop.scala:56)
	at org.apache.spark.repl.SparkILoop$$anonfun$process$1.apply$mcZ$sp(SparkILoop.scala:930)
	at org.apache.spark.repl.SparkILoop$$anonfun$process$1.apply(SparkILoop.scala:884)
	at org.apache.spark.repl.SparkILoop$$anonfun$process$1.apply(SparkILoop.scala:884)
	at scala.tools.nsc.util.ScalaClassLoader$.savingContextLoader(ScalaClassLoader.scala:135)
	at org.apache.spark.repl.SparkILoop.process(SparkILoop.scala:884)
	at org.apache.spark.repl.SparkILoop.process(SparkILoop.scala:982)
	at org.apache.spark.repl.Main$.main(Main.scala:31)
	at org.apache.spark.repl.Main.main(Main.scala)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.apache.spark.deploy.SparkSubmit$.launch(SparkSubmit.scala:292)
	at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:55)
	at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)
14/06/08 23:58:23 WARN AbstractLifeCycle: FAILED org.eclipse.jetty.server.Server@7439e55a: java.net.BindException: Address already in use
java.net.BindException: Address already in use
	at sun.nio.ch.Net.bind0(Native Method)
	at sun.nio.ch.Net.bind(Net.java:444)
	at sun.nio.ch.Net.bind(Net.java:436)
	at sun.nio.ch.ServerSocketChannelImpl.bind(ServerSocketChannelImpl.java:214)
	at sun.nio.ch.ServerSocketAdaptor.bind(ServerSocketAdaptor.java:74)
	at org.eclipse.jetty.server.nio.SelectChannelConnector.open(SelectChannelConnector.java:187)
	at org.eclipse.jetty.server.AbstractConnector.doStart(AbstractConnector.java:316)
	at org.eclipse.jetty.server.nio.SelectChannelConnector.doStart(SelectChannelConnector.java:265)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
	at org.eclipse.jetty.server.Server.doStart(Server.java:293)
	at org.eclipse.jetty.util.component.AbstractLifeCycle.start(AbstractLifeCycle.java:64)
	at org.apache.spark.ui.JettyUtils$$anonfun$1.apply$mcV$sp(JettyUtils.scala:192)
	at org.apache.spark.ui.JettyUtils$$anonfun$1.apply(JettyUtils.scala:192)
	at org.apache.spark.ui.JettyUtils$$anonfun$1.apply(JettyUtils.scala:192)
	at scala.util.Try$.apply(Try.scala:161)
	at org.apache.spark.ui.JettyUtils$.connect$1(JettyUtils.scala:191)
	at org.apache.spark.ui.JettyUtils$.startJettyServer(JettyUtils.scala:205)
	at org.apache.spark.ui.WebUI.bind(WebUI.scala:99)
	at org.apache.spark.SparkContext.<init>(SparkContext.scala:223)
	at org.apache.spark.repl.SparkILoop.createSparkContext(SparkILoop.scala:957)
	at $line3.$read$$iwC$$iwC.<init>(<console>:8)
	at $line3.$read$$iwC.<init>(<console>:14)
	at $line3.$read.<init>(<console>:16)
	at $line3.$read$.<init>(<console>:20)
	at $line3.$read$.<clinit>(<console>)
	at $line3.$eval$.<init>(<console>:7)
	at $line3.$eval$.<clinit>(<console>)
	at $line3.$eval.$print(<console>)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.apache.spark.repl.SparkIMain$ReadEvalPrint.call(SparkIMain.scala:788)
	at org.apache.spark.repl.SparkIMain$Request.loadAndRun(SparkIMain.scala:1056)
	at org.apache.spark.repl.SparkIMain.loadAndRunReq$1(SparkIMain.scala:614)
	at org.apache.spark.repl.SparkIMain.interpret(SparkIMain.scala:645)
	at org.apache.spark.repl.SparkIMain.interpret(SparkIMain.scala:609)
	at org.apache.spark.repl.SparkILoop.reallyInterpret$1(SparkILoop.scala:796)
	at org.apache.spark.repl.SparkILoop.interpretStartingWith(SparkILoop.scala:841)
	at org.apache.spark.repl.SparkILoop.command(SparkILoop.scala:753)
	at org.apache.spark.repl.SparkILoopInit$$anonfun$initializeSpark$1.apply(SparkILoopInit.scala:121)
	at org.apache.spark.repl.SparkILoopInit$$anonfun$initializeSpark$1.apply(SparkILoopInit.scala:120)
	at org.apache.spark.repl.SparkIMain.beQuietDuring(SparkIMain.scala:263)
	at org.apache.spark.repl.SparkILoopInit$class.initializeSpark(SparkILoopInit.scala:120)
	at org.apache.spark.repl.SparkILoop.initializeSpark(SparkILoop.scala:56)
	at org.apache.spark.repl.SparkILoop$$anonfun$process$1$$anonfun$apply$mcZ$sp$5.apply$mcV$sp(SparkILoop.scala:913)
	at org.apache.spark.repl.SparkILoopInit$class.runThunks(SparkILoopInit.scala:142)
	at org.apache.spark.repl.SparkILoop.runThunks(SparkILoop.scala:56)
	at org.apache.spark.repl.SparkILoopInit$class.postInitialization(SparkILoopInit.scala:104)
	at org.apache.spark.repl.SparkILoop.postInitialization(SparkILoop.scala:56)
	at org.apache.spark.repl.SparkILoop$$anonfun$process$1.apply$mcZ$sp(SparkILoop.scala:930)
	at org.apache.spark.repl.SparkILoop$$anonfun$process$1.apply(SparkILoop.scala:884)
	at org.apache.spark.repl.SparkILoop$$anonfun$process$1.apply(SparkILoop.scala:884)
	at scala.tools.nsc.util.ScalaClassLoader$.savingContextLoader(ScalaClassLoader.scala:135)
	at org.apache.spark.repl.SparkILoop.process(SparkILoop.scala:884)
	at org.apache.spark.repl.SparkILoop.process(SparkILoop.scala:982)
	at org.apache.spark.repl.Main$.main(Main.scala:31)
	at org.apache.spark.repl.Main.main(Main.scala)
	at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
	at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(Method.java:606)
	at org.apache.spark.deploy.SparkSubmit$.launch(SparkSubmit.scala:292)
	at org.apache.spark.deploy.SparkSubmit$.main(SparkSubmit.scala:55)
	at org.apache.spark.deploy.SparkSubmit.main(SparkSubmit.scala)
14/06/08 23:58:23 INFO JettyUtils: Failed to create UI at port, 4040. Trying again.
14/06/08 23:58:23 INFO JettyUtils: Error was: Failure(java.net.BindException: Address already in use)
14/06/08 23:58:23 INFO SparkUI: Started SparkUI at http://aash-mbp.local:4041
````

After:
```
14/06/09 00:04:12 INFO JettyUtils: Failed to create UI at port, 4040. Trying again.
14/06/09 00:04:12 INFO JettyUtils: Error was: Failure(java.net.BindException: Address already in use)
14/06/09 00:04:12 INFO Server: jetty-8.y.z-SNAPSHOT
14/06/09 00:04:12 INFO AbstractConnector: Started SelectChannelConnector@0.0.0.0:4041
14/06/09 00:04:12 INFO SparkUI: Started SparkUI at http://aash-mbp.local:4041
```

Lengthy logging comes from this line of code in Jetty: http://grepcode.com/file/repo1.maven.org/maven2/org.eclipse.jetty.aggregate/jetty-all/9.1.3.v20140225/org/eclipse/jetty/util/component/AbstractLifeCycle.java#210

Author: Andrew Ash <andrew@andrewash.com>

Closes #1019 from ash211/SPARK-1902 and squashes the following commits:

0dd02f7 [Andrew Ash] Leave old org.eclipse.jetty silencing in place
1e2866b [Andrew Ash] Address CR comments
9d85eed [Andrew Ash] SPARK-1902 Silence stacktrace from logs when doing port failover to port n+1
[SPARK-1970] Update unit test in XORShiftRandomSuite to use ChiSquareTest from commons-math3

Updating the chisquare unit test in XORShiftRandomSuite to use the ChiSquareTest in commons-math3 instead of hardcoding the chisquare statistic for the desired confidence interval.

Author: Doris Xin <doris.s.xin@gmail.com>

Closes #1073 from dorx/math3Unit and squashes the following commits:

da0e891 [Doris Xin] remove math3 from common pom
9954143 [Doris Xin] merge master
c19948f [Doris Xin] Merge branch 'master' into math3Unit
8f84f19 [Doris Xin] [SPARK-1970] unit test in XORShiftRandomSuite
ffea61a [Doris Xin] SPARK-1939: Refactor takeSample method in RDD
1441977 [Doris Xin] SPARK-1939 Refactor takeSample method in RDD to use ScaSRS
HOTFIX: Fixing style error introduced by 08d0ac
[SPARK-2061] Made splits deprecated in JavaRDDLike

The jira for the issue can be found at: https://issues.apache.org/jira/browse/SPARK-2061
Most of spark has used over to consistently using `partitions` instead of `splits`. We should do likewise and add a `partitions` method to JavaRDDLike and have `splits` just call that. We should also go through all cases where other API's (e.g. Python) call `splits` and we should change those to use the newer API.

Author: Anant <anant.asty@gmail.com>

Closes #1062 from anantasty/SPARK-2061 and squashes the following commits:

b83ce6b [Anant] Fixed syntax issue
21f9210 [Anant] Fixed version number in deprecation string
9315b76 [Anant] made related changes to use partitions in python api
8c62dd1 [Anant] Made splits deprecated in JavaRDDLike
Fix some tests.

- JavaAPISuite was trying to compare a bare path with a URI. Fix by
  extracting the path from the URI, since we know it should be a
  local path anyway/

- b9be1609 excluded the ASM dependency everywhere, but easymock needs
  it (because cglib needs it). So re-add the dependency, with test
  scope this time.

The second one above actually uncovered a weird situation: the maven
test target works, even though I can't find the class sbt complains
about in its classpath. sbt complains with:

  [error] Uncaught exception when running org.apache.spark.util
  .random.RandomSamplerSuite: java.lang.NoClassDefFoundError:
  org/objectweb/asm/Type

To avoid more weirdness caused by that, I explicitly added the asm
dependency to both maven and sbt (for tests only), and verified
the classes don't end up in the final assembly.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #917 from vanzin/flaky-tests and squashes the following commits:

d022320 [Marcelo Vanzin] Fix some tests.
[SQL] Pass SQLContext instead of SparkContext into physical operators.

This makes it easier to use config options in operators.

Author: Reynold Xin <rxin@apache.org>

Closes #1164 from rxin/sqlcontext and squashes the following commits:

797b2fd [Reynold Xin] Pass SQLContext instead of SparkContext into physical operators.
[SQL] Break hiveOperators.scala into multiple files.

The single file was getting very long (500+ loc).

Author: Reynold Xin <rxin@apache.org>

Closes #1166 from rxin/hiveOperators and squashes the following commits:

5b43068 [Reynold Xin] [SQL] Break hiveOperators.scala into multiple files.
HOTFIX: Fix missing MIMA ignore
HOTFIX: Add excludes for new MIMA files
SPARK-1996. Remove use of special Maven repo for Akka

Just following up Matei's suggestion to remove the Akka repo references. Builds and the audit-release script appear OK.

Author: Sean Owen <sowen@cloudera.com>

Closes #1170 from srowen/SPARK-1996 and squashes the following commits:

5ca2930 [Sean Owen] Remove outdated Akka repository references
SPARK-2231: dev/run-tests should include YARN and use a recent Hadoop version

...rsion

Author: Patrick Wendell <pwendell@gmail.com>

Closes #1175 from pwendell/test-hadoop-version and squashes the following commits:

9210ef4 [Patrick Wendell] SPARK-2231: dev/run-tests should include YARN and use a recent Hadoop version
SPARK-2034. KafkaInputDStream doesn't close resources and may prevent JVM shutdown

Tobias noted today on the mailing list:

========

I am trying to use Spark Streaming with Kafka, which works like a
charm – except for shutdown. When I run my program with "sbt
run-main", sbt will never exit, because there are two non-daemon
threads left that don't die.
I created a minimal example at
<https://gist.github.com/tgpfeiffer/b1e765064e983449c6b6#file-kafkadoesntshutdown-scala>.
It starts a StreamingContext and does nothing more than connecting to
a Kafka server and printing what it receives. Using the `future
Unknown macro: { ... }
` construct, I shut down the StreamingContext after some seconds and
then print the difference between the threads at start time and at end
time. The output can be found at
<https://gist.github.com/tgpfeiffer/b1e765064e983449c6b6#file-output1>.
There are a number of threads remaining that will prevent sbt from
exiting.
When I replace `KafkaUtils.createStream(...)` with a call that does
exactly the same, except that it calls `consumerConnector.shutdown()`
in `KafkaReceiver.onStop()` (which it should, IMO), the output is as
shown at <https://gist.github.com/tgpfeiffer/b1e765064e983449c6b6#file-output2>.
Does anyone have any idea what is going on here and why the program
doesn't shut down properly? The behavior is the same with both kafka
0.8.0 and 0.8.1.1, by the way.

========

Something similar was noted last year:

http://mail-archives.apache.org/mod_mbox/spark-dev/201309.mbox/%3C1380220041.2428.YahooMailNeo@web160804.mail.bf1.yahoo.com%3E

KafkaInputDStream doesn't close `ConsumerConnector` in `onStop()`, and does not close the `Executor` it creates. The latter leaves non-daemon threads and can prevent the JVM from shutting down even if streaming is closed properly.

Author: Sean Owen <sowen@cloudera.com>

Closes #980 from srowen/SPARK-2034 and squashes the following commits:

9f31a8d [Sean Owen] Restore ClassTag to private class because MIMA flags it; is the shadowing intended?
2d579a8 [Sean Owen] Close ConsumerConnector in onStop; shutdown() the local Executor that is created so that its threads stop when done; close the Zookeeper client even on exception; fix a few typos; log exceptions that otherwise vanish
SPARK-1316. Remove use of Commons IO

Commons IO is actually barely used, and is not a declared dependency. This just replaces with equivalents from the JDK and Guava.

Author: Sean Owen <sowen@cloudera.com>

Closes #1173 from srowen/SPARK-1316 and squashes the following commits:

2eb53db [Sean Owen] Reorder Guava import
8fde404 [Sean Owen] Remove use of Commons IO, which is not actually a dependency
SPARK-2229: FileAppender throw an llegalArgumentException in jdk6

Author: witgo <witgo@qq.com>

Closes #1174 from witgo/SPARK-2229 and squashes the following commits:

f85f321 [witgo] FileAppender throw anIllegalArgumentException in JDK6
e1a8da8 [witgo] SizeBasedRollingPolicy throw an java.lang.IllegalArgumentException in JDK6
SPARK-2241: quote command line args in ec2 script

To preserve quoted command line args (in case options have space in them).

Author: Ori Kremer <ori.kremer@gmail.com>

Closes #1169 from orikremer/quote_cmd_line_args and squashes the following commits:

67e2aa1 [Ori Kremer] quote command line args
SPARK-2166 - Listing of instances to be terminated before the prompt

Will list the EC2 instances before detroying the cluster.
This was added because it can be scary to destroy EC2
instances without knowing which one will be impacted.

Author: Jean-Martin Archer <jeanmartin.archer@pulseenergy.com>

This patch had conflicts when merged, resolved by
Committer: Patrick Wendell <pwendell@gmail.com>

Closes #270 from j-martin/master and squashes the following commits:

826455f [Jean-Martin Archer] [SPARK-2611] Implementing recommendations
27b0a36 [Jean-Martin Archer] Listing of instances to be terminated before the prompt Will list the EC2 instances before detroying the cluster. This was added because it can be scary to destroy EC2 instances without knowing which one will be impacted.
[SPARK-1395] Fix "local:" URI support in Yarn mode (again).

Recent changes ignored the fact that path may be defined with "local:"
URIs, which means they need to be explicitly added to the classpath
everywhere a remote process is started. This change fixes that by:

- Using the correct methods to add paths to the classpath
- Creating SparkConf settings for the Spark jar itself and for the
  user's jar
- Propagating those two settings to the remote processes where needed

This ensures that both in client and in cluster mode, the driver has
the necessary info to build the executor's classpath and have things
still work when they contain "local:" references.

The change also fixes some confusion in ClientBase about whether
to use SparkConf or system properties to propagate config options to
the driver and executors, by standardizing on using data held by
SparkConf.

On the cleanup front, I removed the hacky way that log4j configuration
was being propagated to handle the "local:" case. It's much more cleanly
(and generically) handled by using spark-submit arguments (--files to
upload a config file, or setting spark.executor.extraJavaOptions to pass
JVM arguments and use a local file).

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #560 from vanzin/yarn-local-2 and squashes the following commits:

4e7f066 [Marcelo Vanzin] Correctly propagate SPARK_JAVA_OPTS to driver/executor.
6a454ea [Marcelo Vanzin] Use constants for PWD in test.
6dd5943 [Marcelo Vanzin] Fix propagation of config options to driver / executor.
b2e377f [Marcelo Vanzin] Review feedback.
93c3f85 [Marcelo Vanzin] Fix ClassCastException in test.
e5c682d [Marcelo Vanzin] Fix cluster mode, restore SPARK_LOG4J_CONF.
1dfbb40 [Marcelo Vanzin] Add documentation for spark.yarn.jar.
bbdce05 [Marcelo Vanzin] [SPARK-1395] Fix "local:" URI support in Yarn mode (again).