Include the key name when failing on an invalid value.

Admittedly a really small tweak.

Author: Stephen Haberman <stephen@exigencecorp.com>

Closes #3514 from stephenh/include-key-name-in-npe and squashes the following commits:

937740a [Stephen Haberman] Include the key name when failing on an invalid value.
[SPARK-4057] Use -agentlib instead of -Xdebug in sbt-launch-lib.bash for debugging

In -launch-lib.bash, -Xdebug option is used for debugging. We should use -agentlib option for Java 6+.

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

Closes #2904 from sarutak/SPARK-4057 and squashes the following commits:

39b5320 [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into SPARK-4057
26b4af8 [Kousuke Saruta] Improved java option for debugging
[SPARK-4505][Core] Add a ClassTag parameter to CompactBuffer[T]

Added a ClassTag parameter to CompactBuffer. So CompactBuffer[T] can create primitive arrays for primitive types. It will reduce the memory usage for primitive types significantly and only pay minor performance lost.

Here is my test code:
```Scala
  // Call org.apache.spark.util.SizeEstimator.estimate
  def estimateSize(obj: AnyRef): Long = {
    val c = Class.forName("org.apache.spark.util.SizeEstimator$")
    val f = c.getField("MODULE$")
    val o = f.get(c)
    val m = c.getMethod("estimate", classOf[Object])
    m.setAccessible(true)
    m.invoke(o, obj).asInstanceOf[Long]
  }

  sc.parallelize(1 to 10000).groupBy(_ => 1).foreach {
    case (k, v) =>
      println(v.getClass() + " size: " + estimateSize(v))
  }
```

Using the previous CompactBuffer outputed
```
class org.apache.spark.util.collection.CompactBuffer size: 313358
```

Using the new CompactBuffer outputed
```
class org.apache.spark.util.collection.CompactBuffer size: 65712
```

In this case, the new `CompactBuffer` only used 20% memory of the previous one. It's really helpful for `groupByKey` when using a primitive value.

Author: zsxwing <zsxwing@gmail.com>

Closes #3378 from zsxwing/SPARK-4505 and squashes the following commits:

4abdbba [zsxwing] Add a ClassTag parameter to reduce the memory usage of CompactBuffer[T] when T is a primitive type
SPARK-4507: PR merge script should support closing multiple JIRA tickets

This will fix SPARK-4507.

For pull requests that reference multiple JIRAs in their titles, it would be helpful if the PR merge script offered to close all of them.

Author: Takayuki Hasegawa <takayuki.hasegawa0311@gmail.com>

Closes #3428 from hase1031/SPARK-4507 and squashes the following commits:

bf6d64b [Takayuki Hasegawa] SPARK-4507: try to resolve issue when no JIRAs in title
401224c [Takayuki Hasegawa] SPARK-4507: moved codes as before
ce89021 [Takayuki Hasegawa] SPARK-4507: PR merge script should support closing multiple JIRA tickets
[DOCS][BUILD] Add instruction to use change-version-to-2.11.sh in 'Building for Scala 2.11'.

To build with Scala 2.11, we have to execute `change-version-to-2.11.sh` before Maven execute, otherwise inter-module dependencies are broken.

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

Closes #3361 from ueshin/docs/building-spark_2.11 and squashes the following commits:

1d29126 [Takuya UESHIN] Add instruction to use change-version-to-2.11.sh in 'Building for Scala 2.11'.
SPARK-2143 [WEB UI] Add Spark version to UI footer

This PR adds the Spark version number to the UI footer; this is how it looks:

![screen shot 2014-11-21 at 22 58 40](https://cloud.githubusercontent.com/assets/822522/5157738/f4822094-7316-11e4-98f1-333a535fdcfa.png)

Author: Sean Owen <sowen@cloudera.com>

Closes #3410 from srowen/SPARK-2143 and squashes the following commits:

e9b3a7a [Sean Owen] Add Spark version to footer
[SPARK-4623]Add the some error infomation if using spark-sql in yarn-cluster mode

If using spark-sql in yarn-cluster mode, print an error infomation just as the spark shell in yarn-cluster mode.

Author: carlmartin <carlmartinmax@gmail.com>
Author: huangzhaowei <carlmartinmax@gmail.com>

Closes #3479 from SaintBacchus/sparkSqlShell and squashes the following commits:

35829a9 [carlmartin] improve the description of comment
e6c1eb7 [carlmartin] add a comment in bin/spark-sql to remind user who wants to change the class
f1c5c8d [carlmartin] Merge branch 'master' into sparkSqlShell
8e112c5 [huangzhaowei] singular form
ec957bc [carlmartin] Add the some error infomation if using spark-sql in yarn-cluster mode
7bcecc2 [carlmartin] Merge branch 'master' of https://github.com/apache/spark into codereview
4fad75a [carlmartin] Add the Error infomation using spark-sql in yarn-cluster mode
[SPARK-4656][Doc] Typo in Programming Guide markdown

Grammatical error in Programming Guide document

Author: lewuathe <lewuathe@me.com>

Closes #3412 from Lewuathe/typo-programming-guide and squashes the following commits:

a3e2f00 [lewuathe] Typo in Programming Guide markdown
[DOC] Fixes formatting typo in SQL programming guide

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Author: Cheng Lian <lian@databricks.com>

Closes #3498 from liancheng/fix-sql-doc-typo and squashes the following commits:

865ecd7 [Cheng Lian] Fixes formatting typo in SQL programming guide
MAINTENANCE: Automated closing of pull requests.

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

Closes #2915 (close requested by 'JoshRosen')
Closes #3140 (close requested by 'JoshRosen')
Closes #3366 (close requested by 'JoshRosen')
[SPARK-4632] version update

Author: Prabeesh K <prabsmails@gmail.com>

Closes #3495 from prabeesh/master and squashes the following commits:

ab03d50 [Prabeesh K] Update pom.xml
8c6437e [Prabeesh K] Revert
e10b40a [Prabeesh K] version update
dbac9eb [Prabeesh K] Revert
ec0b1c3 [Prabeesh K] [SPARK-4632] version update
a835505 [Prabeesh K] [SPARK-4632] version update
831391b [Prabeesh K]  [SPARK-4632] version update
Merge branch 'master' of github.com:apache/spark