[SPARK-4932] Add help comments in Analytics

Trivial modifications for usability.

Author: Takeshi Yamamuro <linguin.m.s@gmail.com>

Closes #3775 from maropu/AddHelpCommentInAnalytics and squashes the following commits:

fbea8f5 [Takeshi Yamamuro] Add help comments in Analytics
[SPARK-4914][Build] Cleans lib_managed before compiling with Hive 0.13.1

This PR tries to fix the Hive tests failure encountered in PR #3157 by cleaning `lib_managed` before building assembly jar against Hive 0.13.1 in `dev/run-tests`. Otherwise two sets of datanucleus jars would be left in `lib_managed` and may mess up class paths while executing Hive test suites. Please refer to [this thread] [1] for details. A clean build would be even safer, but we only clean `lib_managed` here to save build time.

This PR also takes the chance to clean up some minor typos and formatting issues in the comments.

[1]: https://github.com/apache/spark/pull/3157#issuecomment-67656488

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Author: Cheng Lian <lian@databricks.com>

Closes #3756 from liancheng/clean-lib-managed and squashes the following commits:

e2bd21d [Cheng Lian] Adds lib_managed to clean set
c9f2f3e [Cheng Lian] Cleans lib_managed before compiling with Hive 0.13.1
[SPARK-4730][YARN] Warn against deprecated YARN settings

See https://issues.apache.org/jira/browse/SPARK-4730.

Author: Andrew Or <andrew@databricks.com>

Closes #3590 from andrewor14/yarn-settings and squashes the following commits:

36e0753 [Andrew Or] Merge branch 'master' of github.com:apache/spark into yarn-settings
dcd1316 [Andrew Or] Warn against deprecated YARN settings
[SPARK-4913] Fix incorrect event log path

SPARK-2261 uses a single file to log events for an app. `eventLogDir` in `ApplicationDescription` is replaced with `eventLogFile`. However, `ApplicationDescription` in `SparkDeploySchedulerBackend` is initialized with `SparkContext`'s `eventLogDir`. It is just the log directory, not the actual log file path. `Master.rebuildSparkUI` can not correctly rebuild a new SparkUI for the app.

Because the `ApplicationDescription` is remotely registered with `Master` and the app's id is then generated in `Master`, we can not get the app id in advance before registration. So the received description needs to be modified with correct `eventLogFile` value.

Author: Liang-Chi Hsieh <viirya@gmail.com>

Closes #3755 from viirya/fix_app_logdir and squashes the following commits:

5e0ea35 [Liang-Chi Hsieh] Revision for comment.
b5730a1 [Liang-Chi Hsieh] Fix incorrect event log path.

Closes #3777 (a duplicate PR for the same JIRA)
[SPARK-4802] [streaming] Remove receiverInfo once receiver is de-registered

  Once the streaming receiver is de-registered at executor, the `ReceiverTrackerActor` needs to
remove the corresponding reveiverInfo from the `receiverInfo` map at `ReceiverTracker`.

Author: Ilayaperumal Gopinathan <igopinathan@pivotal.io>

Closes #3647 from ilayaperumalg/receiverInfo-RTracker and squashes the following commits:

6eb97d5 [Ilayaperumal Gopinathan] Polishing based on the review
3640c86 [Ilayaperumal Gopinathan] Remove receiverInfo once receiver is de-registered
[SPARK-4671][Streaming]Do not replicate streaming block when WAL is enabled

Currently streaming block will be replicated when specific storage level is set, since WAL is already fault tolerant, so replication is needless and will hurt the throughput of streaming application.

Hi tdas , as per discussed about this issue, I fixed with this implementation, I'm not is this the way you want, would you mind taking a look at it? Thanks a lot.

Author: jerryshao <saisai.shao@intel.com>

Closes #3534 from jerryshao/SPARK-4671 and squashes the following commits:

500b456 [jerryshao] Do not replicate streaming block when WAL is enabled
[SPARK-4606] Send EOF to child JVM when there's no more data to read.

Author: Marcelo Vanzin <vanzin@cloudera.com>

Closes #3460 from vanzin/SPARK-4606 and squashes the following commits:

031207d [Marcelo Vanzin] [SPARK-4606] Send EOF to child JVM when there's no more data to read.
[SPARK-4860][pyspark][sql] speeding up `sample()` and `takeSample()`

This PR modifies the python `SchemaRDD` to use `sample()` and `takeSample()` from Scala instead of the slower python implementations from `rdd.py`. This is worthwhile because the `Row`'s are already serialized as Java objects.

In order to use the faster `takeSample()`, a `takeSampleToPython()` method was implemented in `SchemaRDD.scala` following the pattern of `collectToPython()`.

Author: jbencook <jbenjamincook@gmail.com>
Author: J. Benjamin Cook <jbenjamincook@gmail.com>

Closes #3764 from jbencook/master and squashes the following commits:

6fbc769 [J. Benjamin Cook] [SPARK-4860][pyspark][sql] fixing sloppy indentation for takeSampleToPython() arguments
5170da2 [J. Benjamin Cook] [SPARK-4860][pyspark][sql] fixing typo: from RDD to SchemaRDD
de22f70 [jbencook] [SPARK-4860][pyspark][sql] using sample() method from JavaSchemaRDD
b916442 [jbencook] [SPARK-4860][pyspark][sql] adding sample() to JavaSchemaRDD
020cbdf [jbencook] [SPARK-4860][pyspark][sql] using Scala implementations of `sample()` and `takeSample()`
[SPARK-4881][Minor] Use SparkConf#getBoolean instead of get().toBoolean

It's really a minor issue.

In ApplicationMaster, there is code like as follows.

    val preserveFiles = sparkConf.get("spark.yarn.preserve.staging.files", "false").toBoolean

I think, the code can be simplified like as follows.

    val preserveFiles = sparkConf.getBoolean("spark.yarn.preserve.staging.files", false)

Author: Kousuke Saruta <sarutak@oss.nttdata.co.jp>

Closes #3733 from sarutak/SPARK-4881 and squashes the following commits:

1771430 [Kousuke Saruta] Modified the code like sparkConf.get(...).toBoolean to sparkConf.getBoolean(...)
c63daa0 [Kousuke Saruta] Simplified code
SPARK-4297 [BUILD] Build warning fixes omnibus

There are a number of warnings generated in a normal, successful build right now. They're mostly Java unchecked cast warnings, which can be suppressed. But there's a grab bag of other Scala language warnings and so on that can all be easily fixed. The forthcoming PR fixes about 90% of the build warnings I see now.

Author: Sean Owen <sowen@cloudera.com>

Closes #3157 from srowen/SPARK-4297 and squashes the following commits:

8c9e469 [Sean Owen] Suppress unchecked cast warnings, and several other build warning fixes
[SPARK-4873][Streaming] Use `Future.zip` instead of `Future.flatMap`(for-loop) in WriteAheadLogBasedBlockHandler

Use `Future.zip` instead of `Future.flatMap`(for-loop). `zip` implies these two Futures will run concurrently, while `flatMap` usually means one Future depends on the other one.

Author: zsxwing <zsxwing@gmail.com>

Closes #3721 from zsxwing/SPARK-4873 and squashes the following commits:

46a2cd9 [zsxwing] Use Future.zip instead of Future.flatMap(for-loop)
[SPARK-4953][Doc] Fix the description of building Spark with YARN

At the section "Specifying the Hadoop Version" In building-spark.md, there is description about building with YARN with Hadoop 0.23.
Spark 1.3.0 will not support Hadoop 0.23 so we should fix the description.

Author: Kousuke Saruta <sarutak@oss.nttdata.co.jp>

Closes #3787 from sarutak/SPARK-4953 and squashes the following commits:

ee9c355 [Kousuke Saruta] Removed description related to a specific vendor
9ab0c24 [Kousuke Saruta] Fix the description about building SPARK with YARN
Fix "Building Spark With Maven" link in README.md

Corrected link to the Building Spark with Maven page from its original (http://spark.apache.org/docs/latest/building-with-maven.html) to the current page (http://spark.apache.org/docs/latest/building-spark.html)

Author: Denny Lee <denny.g.lee@gmail.com>

Closes #3802 from dennyglee/patch-1 and squashes the following commits:

15f601a [Denny Lee] Update README.md
[EC2] Update default Spark version to 1.2.0

Now that 1.2.0 is out, let's update the default Spark version.

Author: Nicholas Chammas <nicholas.chammas@gmail.com>

Closes #3793 from nchammas/patch-1 and squashes the following commits:

3255832 [Nicholas Chammas] add 1.2.0 version to Spark-Shark map
ec0e904 [Nicholas Chammas] [EC2] Update default Spark version to 1.2.0
[EC2] Update mesos/spark-ec2 branch to branch-1.3

Going forward, we'll use matching branch names across the mesos/spark-ec2 and apache/spark repositories, per [the discussion here](https://github.com/mesos/spark-ec2/pull/85#issuecomment-68069589).

Author: Nicholas Chammas <nicholas.chammas@gmail.com>

Closes #3804 from nchammas/patch-2 and squashes the following commits:

cd2c0d4 [Nicholas Chammas] [EC2] Update mesos/spark-ec2 branch to branch-1.3
[SPARK-4537][Streaming] Expand StreamingSource to add more metrics

Add `processingDelay`, `schedulingDelay` and `totalDelay` for the last completed batch. Add `lastReceivedBatchRecords` and `totalReceivedBatchRecords` to the received records counting.

Author: jerryshao <saisai.shao@intel.com>

Closes #3466 from jerryshao/SPARK-4537 and squashes the following commits:

00f5f7f [jerryshao] Change the code style and add totalProcessedRecords
44721a6 [jerryshao] Further address the comments
c097ddc [jerryshao] Address the comments
02dd44f [jerryshao] Fix the addressed comments
c7a9376 [jerryshao] Expand StreamingSource to add more metrics
[SPARK-4608][Streaming] Reorganize StreamingContext implicit to improve API convenience

There is only one implicit function `toPairDStreamFunctions` in `StreamingContext`. This PR did similar reorganization like [SPARK-4397](https://issues.apache.org/jira/browse/SPARK-4397).

Compiled the following codes with Spark Streaming 1.1.0 and ran it with this PR. Everything is fine.
```Scala
import org.apache.spark._
import org.apache.spark.streaming._
import org.apache.spark.streaming.StreamingContext._

object StreamingApp {

  def main(args: Array[String]) {
    val conf = new SparkConf().setMaster("local[2]").setAppName("FileWordCount")
    val ssc = new StreamingContext(conf, Seconds(10))
    val lines = ssc.textFileStream("/some/path")
    val words = lines.flatMap(_.split(" "))
    val pairs = words.map(word => (word, 1))
    val wordCounts = pairs.reduceByKey(_ + _)
    wordCounts.print()

    ssc.start()
    ssc.awaitTermination()
  }
}
```

Author: zsxwing <zsxwing@gmail.com>

Closes #3464 from zsxwing/SPARK-4608 and squashes the following commits:

aa6d44a [zsxwing] Fix a copy-paste error
f74c190 [zsxwing] Merge branch 'master' into SPARK-4608
e6f9cc9 [zsxwing] Update the docs
27833bb [zsxwing] Remove `import StreamingContext._`
c15162c [zsxwing] Reorganize StreamingContext implicit to improve API convenience
SPARK-4971: Fix typo in BlockGenerator comment

Author: CodingCat <zhunansjtu@gmail.com>

Closes #3807 from CodingCat/new_branch and squashes the following commits:

5167f01 [CodingCat] fix typo in the comment
fixed merge conflicts with dev/run-tests, properly quoted args in sbt/sbt, fixed bug where relative paths would fail if passed in from build/mvn