Cut down the granularity of travis tests.

This PR amortizes the cost of downloading all the jars and compiling core across more test cases.  In one anecdotal run this change takes the cumulative time down from ~80 minutes to ~40 minutes.

Author: Michael Armbrust <michael@databricks.com>

Closes #255 from marmbrus/travis and squashes the following commits:

506b22d [Michael Armbrust] Cut down the granularity of travis tests so we can amortize the cost of compilation.
SPARK-1330 removed extra echo from comput_classpath.sh

remove the extra echo which prevents spark-class from working.  Note that I did not update the comment above it, which is also wrong because I'm not sure what it should do.

Should hive only be included if explicitly built with sbt hive/assembly or should sbt assembly build it?

Author: Thomas Graves <tgraves@apache.org>

Closes #241 from tgravescs/SPARK-1330 and squashes the following commits:

b10d708 [Thomas Graves] SPARK-1330 removed extra echo from comput_classpath.sh
SPARK-1335. Also increase perm gen / code cache for scalatest when invoked via Maven build

I am observing build failures when the Maven build reaches tests in the new SQL components. (I'm on Java 7 / OSX 10.9). The failure is the usual complaint from scala, that it's out of permgen space, or that JIT out of code cache space.

I see that various build scripts increase these both for SBT. This change simply adds these settings to scalatest's arguments. Works for me and seems a bit more consistent.

(I also snuck in cures for new build warnings from new scaladoc. Felt too trivial for a new PR, although it's separate. Just something I also saw while examining the build output.)

Author: Sean Owen <sowen@cloudera.com>

Closes #253 from srowen/SPARK-1335 and squashes the following commits:

c0f2d31 [Sean Owen] Appease scalastyle with a newline at the end of the file
a02679c [Sean Owen] Fix scaladoc errors due to missing links, which are generating build warnings, from some recent doc changes. We apparently can't generate links outside the module.
b2c6a09 [Sean Owen] Add perm gen, code cache settings to scalatest, mirroring SBT settings elsewhere, which allows tests to complete in at least one environment where they are failing. (Also removed a duplicate -Xms setting elsewhere.)
[SPARK-1268] Adding XOR and AND-NOT operations to spark.util.collection.BitSet

Symmetric difference (xor) in particular is useful for computing some distance metrics (e.g. Hamming). Unit tests added.

Author: Petko Nikolov <nikolov@soundcloud.com>

Closes #172 from petko-nikolov/bitset-imprv and squashes the following commits:

451f28b [Petko Nikolov] fixed style mistakes
5beba18 [Petko Nikolov] rm outer loop in andNot test
0e61035 [Petko Nikolov] conform to spark style; rm redundant asserts; more unit tests added; use arraycopy instead of loop
d53cdb9 [Petko Nikolov] rm incidentally added space
4e1df43 [Petko Nikolov] adding xor and and-not to BitSet; unit tests added
[SPARK-1210] Prevent ContextClassLoader of Actor from becoming ClassLoader of Executo...

...r.

Constructor of `org.apache.spark.executor.Executor` should not set context class loader of current thread, which is backend Actor's thread.

Run the following code in local-mode REPL.

```
scala> case class Foo(i: Int)
scala> val ret = sc.parallelize((1 to 100).map(Foo), 10).collect
```

This causes errors as follows:

```
ERROR actor.OneForOneStrategy: [L$line5.$read$$iwC$$iwC$$iwC$$iwC$Foo;
java.lang.ArrayStoreException: [L$line5.$read$$iwC$$iwC$$iwC$$iwC$Foo;
     at scala.runtime.ScalaRunTime$.array_update(ScalaRunTime.scala:88)
     at org.apache.spark.SparkContext$$anonfun$runJob$3.apply(SparkContext.scala:870)
     at org.apache.spark.SparkContext$$anonfun$runJob$3.apply(SparkContext.scala:870)
     at org.apache.spark.scheduler.JobWaiter.taskSucceeded(JobWaiter.scala:56)
     at org.apache.spark.scheduler.DAGScheduler.handleTaskCompletion(DAGScheduler.scala:859)
     at org.apache.spark.scheduler.DAGScheduler.processEvent(DAGScheduler.scala:616)
     at org.apache.spark.scheduler.DAGScheduler$$anonfun$start$1$$anon$2$$anonfun$receive$1.applyOrElse(DAGScheduler.scala:207)
     at akka.actor.ActorCell.receiveMessage(ActorCell.scala:498)
     at akka.actor.ActorCell.invoke(ActorCell.scala:456)
     at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:237)
     at akka.dispatch.Mailbox.run(Mailbox.scala:219)
     at akka.dispatch.ForkJoinExecutorConfigurator$AkkaForkJoinTask.exec(AbstractDispatcher.scala:386)
     at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
     at scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
     at scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
     at scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)
```

This is because the class loaders to deserialize result `Foo` instances might be different from backend Actor's, and the Actor's class loader should be the same as Driver's.

Author: Takuya UESHIN <ueshin@happy-camper.st>

Closes #15 from ueshin/wip/wrongcontextclassloader and squashes the following commits:

d79e8c0 [Takuya UESHIN] Change a parent class loader of ExecutorURLClassLoader.
c6c09b6 [Takuya UESHIN] Add a test to collect objects of class defined in repl.
43e0feb [Takuya UESHIN] Prevent ContextClassLoader of Actor from becoming ClassLoader of Executor.
Make sed do -i '' on OSX

I don't have access to an OSX machine, so if someone could test this that would be great.

Author: Nick Lanham <nick@afternight.org>

Closes #258 from nicklan/osx-sed-fix and squashes the following commits:

a6f158f [Nick Lanham] Also make mktemp work on OSX
558fd6e [Nick Lanham] Make sed do -i '' on OSX
SPARK-1096, a space after comment start style checker.

Author: Prashant Sharma <prashant.s@imaginea.com>

Closes #124 from ScrapCodes/SPARK-1096/scalastyle-comment-check and squashes the following commits:

214135a [Prashant Sharma] Review feedback.
5eba88c [Prashant Sharma] Fixed style checks for ///+ comments.
e54b2f8 [Prashant Sharma] improved message, work around.
83e7144 [Prashant Sharma] removed dependency on scalastyle in plugin, since scalastyle sbt plugin already depends on the right version. Incase we update the plugin we will have to adjust our spark-style project to depend on right scalastyle version.
810a1d6 [Prashant Sharma] SPARK-1096, a space after comment style checker.
ba33193 [Prashant Sharma] scala style as a project