Support cross building for Scala 2.11

Let's give this another go using a version of Hive that shades its JLine dependency.

Author: Prashant Sharma <prashant.s@imaginea.com>
Author: Patrick Wendell <pwendell@gmail.com>

Closes #3159 from pwendell/scala-2.11-prashant and squashes the following commits:

e93aa3e [Patrick Wendell] Restoring -Phive-thriftserver profile and cleaning up build script.
f65d17d [Patrick Wendell] Fixing build issue due to merge conflict
a8c41eb [Patrick Wendell] Reverting dev/run-tests back to master state.
7a6eb18 [Patrick Wendell] Merge remote-tracking branch 'apache/master' into scala-2.11-prashant
583aa07 [Prashant Sharma] REVERT ME: removed hive thirftserver
3680e58 [Prashant Sharma] Revert "REVERT ME: Temporarily removing some Cli tests."
935fb47 [Prashant Sharma] Revert "Fixed by disabling a few tests temporarily."
925e90f [Prashant Sharma] Fixed by disabling a few tests temporarily.
2fffed3 [Prashant Sharma] Exclude groovy from sbt build, and also provide a way for such instances in future.
8bd4e40 [Prashant Sharma] Switched to gmaven plus, it fixes random failures observer with its predecessor gmaven.
5272ce5 [Prashant Sharma] SPARK_SCALA_VERSION related bugs.
2121071 [Patrick Wendell] Migrating version detection to PySpark
b1ed44d [Patrick Wendell] REVERT ME: Temporarily removing some Cli tests.
1743a73 [Patrick Wendell] Removing decimal test that doesn't work with Scala 2.11
f5cad4e [Patrick Wendell] Add Scala 2.11 docs
210d7e1 [Patrick Wendell] Revert "Testing new Hive version with shaded jline"
48518ce [Patrick Wendell] Remove association of Hive and Thriftserver profiles.
e9d0a06 [Patrick Wendell] Revert "Enable thritfserver for Scala 2.10 only"
67ec364 [Patrick Wendell] Guard building of thriftserver around Scala 2.10 check
8502c23 [Patrick Wendell] Enable thritfserver for Scala 2.10 only
e22b104 [Patrick Wendell] Small fix in pom file
ec402ab [Patrick Wendell] Various fixes
0be5a9d [Patrick Wendell] Testing new Hive version with shaded jline
4eaec65 [Prashant Sharma] Changed scripts to ignore target.
5167bea [Prashant Sharma] small correction
a4fcac6 [Prashant Sharma] Run against scala 2.11 on jenkins.
80285f4 [Prashant Sharma] MAven equivalent of setting spark.executor.extraClasspath during tests.
034b369 [Prashant Sharma] Setting test jars on executor classpath during tests from sbt.
d4874cb [Prashant Sharma] Fixed Python Runner suite. null check should be first case in scala 2.11.
6f50f13 [Prashant Sharma] Fixed build after rebasing with master. We should use ${scala.binary.version} instead of just 2.10
e56ca9d [Prashant Sharma] Print an error if build for 2.10 and 2.11 is spotted.
937c0b8 [Prashant Sharma] SCALA_VERSION -> SPARK_SCALA_VERSION
cb059b0 [Prashant Sharma] Code review
0476e5e [Prashant Sharma] Scala 2.11 support with repl and all build changes.
[MLLIB] SPARK-4347: Reducing GradientBoostingSuite run time.

Before:
[info] GradientBoostingSuite:
[info] - Regression with continuous features: SquaredError (22 seconds, 115 milliseconds)
[info] - Regression with continuous features: Absolute Error (19 seconds, 330 milliseconds)
[info] - Binary classification with continuous features: Log Loss (19 seconds, 17 milliseconds)

After:
[info] - Regression with continuous features: SquaredError (7 seconds, 69 milliseconds)
[info] - Regression with continuous features: Absolute Error (4 seconds, 617 milliseconds)
[info] - Binary classification with continuous features: Log Loss (4 seconds, 658 milliseconds)

cc: mengxr, jkbradley

Author: Manish Amde <manish9ue@gmail.com>

Closes #3214 from manishamde/gbt_test_speedup and squashes the following commits:

8994552 [Manish Amde] reducing gbt test run times
[SPARK-3936] Add aggregateMessages, which supersedes mapReduceTriplets

aggregateMessages enables neighborhood computation similarly to mapReduceTriplets, but it introduces two API improvements:

1. Messages are sent using an imperative interface based on EdgeContext rather than by returning an iterator of messages.

2. Rather than attempting bytecode inspection, the required triplet fields must be explicitly specified by the user by passing a TripletFields object. This fixes SPARK-3936.

Additionally, this PR includes the following optimizations for aggregateMessages and EdgePartition:

1. EdgePartition now stores local vertex ids instead of global ids. This avoids hash lookups when looking up vertex attributes and aggregating messages.

2. Internal iterators in aggregateMessages are inlined into a while loop.

In total, these optimizations were tested to provide a 37% speedup on PageRank (uk-2007-05 graph, 10 iterations, 16 r3.2xlarge machines, sped up from 513 s to 322 s).

Subsumes apache/spark#2815. Also fixes SPARK-4173.

Author: Ankur Dave <ankurdave@gmail.com>

Closes #3100 from ankurdave/aggregateMessages and squashes the following commits:

f5b65d0 [Ankur Dave] Address @rxin comments on apache/spark#3054 and apache/spark#3100
1e80aca [Ankur Dave] Add aggregateMessages, which supersedes mapReduceTriplets
194a2df [Ankur Dave] Test triplet iterator in EdgePartition serialization test
e0f8ecc [Ankur Dave] Take activeSet in ExistingEdgePartitionBuilder
c85076d [Ankur Dave] Readability improvements
b567be2 [Ankur Dave] iter.foreach -> while loop
4a566dc [Ankur Dave] Optimizations for mapReduceTriplets and EdgePartition
[SPARK-4355][MLLIB] fix OnlineSummarizer.merge when other.mean is zero

See inline comment about the bug. I also did some code clean-up. dbtsai I moved `update` to a private method of `MultivariateOnlineSummarizer`. I don't think it will cause performance regression, but it would be great if you have some time to test.

Author: Xiangrui Meng <meng@databricks.com>

Closes #3220 from mengxr/SPARK-4355 and squashes the following commits:

5ef601f [Xiangrui Meng] fix OnlineSummarizer.merge when other.mean is zero and some code clean-up