[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
MAINTENANCE: Automated closing of pull requests.

This commit exists to close the following pull requests on Github:

Closes #3456 (close requested by 'pwendell')
Closes #1602 (close requested by 'tdas')
Closes #2633 (close requested by 'tdas')
Closes #2059 (close requested by 'JoshRosen')
Closes #2348 (close requested by 'tdas')
Closes #3662 (close requested by 'tdas')
Closes #2031 (close requested by 'andrewor14')
Closes #265 (close requested by 'JoshRosen')
[SPARK-3787][BUILD] Assembly jar name is wrong when we build with sbt omitting -Dhadoop.version

This PR is another solution for When we build with sbt with profile for hadoop and without property for hadoop version like:

    sbt/sbt -Phadoop-2.2 assembly

jar name is always used default version (1.0.4).

When we build with maven with same condition for sbt, default version for each profile is used.
For instance, if we  build like:

    mvn -Phadoop-2.2 package

jar name is used hadoop2.2.0 as a default version of hadoop-2.2.

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

Closes #3046 from sarutak/fix-assembly-jarname-2 and squashes the following commits:

41ef90e [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into fix-assembly-jarname-2
50c8676 [Kousuke Saruta] Merge branch 'fix-assembly-jarname-2' of github.com:sarutak/spark into fix-assembly-jarname-2
52a1cd2 [Kousuke Saruta] Fixed comflicts
dd30768 [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into fix-assembly-jarname2
f1c90bb [Kousuke Saruta] Fixed SparkBuild.scala in order to read `hadoop.version` property from pom.xml
af6b100 [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into fix-assembly-jarname
c81806b [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into fix-assembly-jarname
ad1f96e [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into fix-assembly-jarname
b2318eb [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into fix-assembly-jarname
5fc1259 [Kousuke Saruta] Fixed typo.
eebbb7d [Kousuke Saruta] Fixed wrong jar name
HOTFIX: Slight tweak on previous commit.

Meant to merge this in when committing SPARK-3787.
[SPARK-3955] Different versions between jackson-mapper-asl and jackson-c...

...ore-asl

- set the same version to jackson-mapper-asl and jackson-core-asl
- It's related with #2818
- coded a same patch from a latest master

Author: Jongyoul Lee <jongyoul@gmail.com>

Closes #3716 from jongyoul/SPARK-3955 and squashes the following commits:

efa29aa [Jongyoul Lee] [SPARK-3955] Different versions between jackson-mapper-asl and jackson-core-asl - set the same version to jackson-mapper-asl and jackson-core-asl
[SPARK-4954][Core] add spark version infomation in log for standalone mode

The master and worker spark version may be not the same with Driver spark version. That is because spark Jar file might be replaced for new application without restarting the spark cluster. So there shall log out the spark-version in both Mater and Worker log.

Author: Zhang, Liye <liye.zhang@intel.com>

Closes #3790 from liyezhang556520/version4Standalone and squashes the following commits:

e05e1e3 [Zhang, Liye] add spark version infomation in log for standalone mode
[SPARK-4952][Core]Handle ConcurrentModificationExceptions in SparkEnv.environmentDetails

Author: GuoQiang Li <witgo@qq.com>

Closes #3788 from witgo/SPARK-4952 and squashes the following commits:

d903529 [GuoQiang Li] Handle ConcurrentModificationExceptions in SparkEnv.environmentDetails
[SPARK-4501][Core] - Create build/mvn to automatically download maven/zinc/scalac

Creates a top level directory script (as `build/mvn`) to automatically download zinc and the specific version of scala used to easily build spark. This will also download and install maven if the user doesn't already have it and all packages are hosted under the `build/` directory. Tested on both Linux and OSX OS's and both work. All commands pass through to the maven binary so it acts exactly as a traditional maven call would.

Author: Brennon York <brennon.york@capitalone.com>

Closes #3707 from brennonyork/SPARK-4501 and squashes the following commits:

0e5a0e4 [Brennon York] minor incorrect doc verbage (with -> this)
9b79e38 [Brennon York] 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
d2d41b6 [Brennon York] added blurb about leverging zinc with build/mvn
b979c58 [Brennon York] updated the merge conflict
c5634de [Brennon York] updated documentation to overview build/mvn, updated all points where sbt/sbt was referenced with build/sbt
b8437ba [Brennon York] set progress bars for curl and wget when not run on jenkins, no progress bar when run on jenkins, moved sbt script to build/sbt, wrote stub and warning under sbt/sbt which calls build/sbt, modified build/sbt to use the correct directory, fixed bug in build/sbt-launch-lib.bash to correctly pull the sbt version
be11317 [Brennon York] added switch to silence download progress only if AMPLAB_JENKINS is set
28d0a99 [Brennon York] updated to remove the python dependency, uses grep instead
7e785a6 [Brennon York] added silent and quiet flags to curl and wget respectively, added single echo output to denote start of a download if download is needed
14a5da0 [Brennon York] removed unnecessary zinc output on startup
1af4a94 [Brennon York] fixed bug with uppercase vs lowercase variable
3e8b9b3 [Brennon York] updated to properly only restart zinc if it was freshly installed
a680d12 [Brennon York] Added comments to functions and tested various mvn calls
bb8cc9d [Brennon York] removed package files
ef017e6 [Brennon York] removed OS complexities, setup generic install_app call, removed extra file complexities, removed help, removed forced install (defaults now), removed double-dash from cli
07bf018 [Brennon York] Updated to specifically handle pulling down the correct scala version
f914dea [Brennon York] Beginning final portions of localized scala home
69c4e44 [Brennon York] working linux and osx installers for purely local mvn build
4a1609c [Brennon York] finalizing working linux install for maven to local ./build/apache-maven folder
cbfcc68 [Brennon York] Changed the default sbt/sbt to build/sbt and added a build/mvn which will automatically download, install, and execute maven with zinc for easier build capability
[SPARK-4966][YARN]The MemoryOverhead value is setted not correctly

Author: meiyoula <1039320815@qq.com>

Closes #3797 from XuTingjun/MemoryOverhead and squashes the following commits:

5a780fc [meiyoula] Update ClientArguments.scala
[SPARK-4982][DOC] `spark.ui.retainedJobs` description is wrong in Spark UI configuration guide

Author: wangxiaojing <u9jing@gmail.com>

Closes #3818 from wangxiaojing/SPARK-4982 and squashes the following commits:

fe2ad5f [wangxiaojing] change stages to jobs
Adde LICENSE Header to build/mvn, build/sbt and sbt/sbt

Recently, build/mvn and build/sbt are added, and sbt/sbt is changed but there are no license headers. Should we add license headers to the scripts right?
If it's not right, please let me correct.

This PR doesn't affect behavior of Spark, I don't file in JIRA.

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

Closes #3817 from sarutak/add-license-header and squashes the following commits:

1abc972 [Kousuke Saruta] Added LICENSE Header