[SPARK-4580] [SPARK-4610] [mllib] [docs] Documentation for tree ensembles + DecisionTree API fix

Major changes:
* Added programming guide sections for tree ensembles
* Added examples for tree ensembles
* Updated DecisionTree programming guide with more info on parameters
* **API change**: Standardized the tree parameter for the number of classes (for classification)

Minor changes:
* Updated decision tree documentation
* Updated existing tree and tree ensemble examples
 * Use train/test split, and compute test error instead of training error.
 * Fixed decision_tree_runner.py to actually use the number of classes it computes from data. (small bug fix)

Note: I know this is a lot of lines, but most is covered by:
* Programming guide sections for gradient boosting and random forests.  (The changes are probably best viewed by generating the docs locally.)
* New examples (which were copied from the programming guide)
* The "numClasses" renaming

I have run all examples and relevant unit tests.

CC: mengxr manishamde codedeft

Author: Joseph K. Bradley <joseph@databricks.com>
Author: Joseph K. Bradley <joseph.kurata.bradley@gmail.com>

Closes #3461 from jkbradley/ensemble-docs and squashes the following commits:

70a75f3 [Joseph K. Bradley] updated forest vs boosting comparison
d1de753 [Joseph K. Bradley] Added note about toString and toDebugString for DecisionTree to migration guide
8e87f8f [Joseph K. Bradley] Combined GBT and RandomForest guides into one ensembles guide
6fab846 [Joseph K. Bradley] small fixes based on review
b9f8576 [Joseph K. Bradley] updated decision tree doc
375204c [Joseph K. Bradley] fixed python style
2b60b6e [Joseph K. Bradley] merged Java RandomForest examples into 1 file.  added header.  Fixed small bug in same example in the programming guide.
706d332 [Joseph K. Bradley] updated python DT runner to print full model if it is small
c76c823 [Joseph K. Bradley] added migration guide for mllib
abe5ed7 [Joseph K. Bradley] added examples for random forest in Java and Python to examples folder
07fc11d [Joseph K. Bradley] Renamed numClassesForClassification to numClasses everywhere in trees and ensembles. This is a breaking API change, but it was necessary to correct an API inconsistency in Spark 1.1 (where Python DecisionTree used numClasses but Scala used numClassesForClassification).
cdfdfbc [Joseph K. Bradley] added examples for GBT
6372a2b [Joseph K. Bradley] updated decision tree examples to use random split.  tested all of them.
ad3e695 [Joseph K. Bradley] added gbt and random forest to programming guide.  still need to update their examples
[Release] Correctly translate contributors name in release notes

This commit involves three main changes:

(1) It separates the translation of contributor names from the
generation of the contributors list. This is largely motivated
by the Github API limit; even if we exceed this limit, we should
at least be able to proceed manually as before. This is why the
translation logic is abstracted into its own script
translate-contributors.py.

(2) When we look for candidate replacements for invalid author
names, we should look for the assignees of the associated JIRAs
too. As a result, the intermediate file must keep track of these.

(3) This provides an interactive mode with which the user can
sit at the terminal and manually pick the candidate replacement
that he/she thinks makes the most sense. As before, there is a
non-interactive mode that picks the first candidate that the
script considers "valid."

TODO: We should have a known_contributors file that stores
known mappings so we don't have to go through all of this
translation every time. This is also valuable because some
contributors simply cannot be automatically translated.
MAINTENANCE: Automated closing of pull requests.

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

Closes #1875 (close requested by 'marmbrus')
Closes #3566 (close requested by 'andrewor14')
Closes #3487 (close requested by 'pwendell')
[SQL] remove unnecessary import

Author: Jacky Li <jacky.likun@huawei.com>

Closes #3585 from jackylk/remove and squashes the following commits:

045423d [Jacky Li] remove unnecessary import
[SPARK-4719][API] Consolidate various narrow dep RDD classes with MapPartitionsRDD

MappedRDD, MappedValuesRDD, FlatMappedValuesRDD, FilteredRDD, GlommedRDD, FlatMappedRDD are not necessary. They can be implemented trivially using MapPartitionsRDD.

Author: Reynold Xin <rxin@databricks.com>

Closes #3578 from rxin/SPARK-4719 and squashes the following commits:

eed9853 [Reynold Xin] Preserve partitioning for filter.
eb1a89b [Reynold Xin] [SPARK-4719][API] Consolidate various narrow dep RDD classes with MapPartitionsRDD.
[SPARK-4685] Include all spark.ml and spark.mllib packages in JavaDoc's MLlib group

This is #3554 from Lewuathe except that I put both `spark.ml` and `spark.mllib` in the group 'MLlib`.

Closes #3554

jkbradley

Author: lewuathe <lewuathe@me.com>
Author: Xiangrui Meng <meng@databricks.com>

Closes #3598 from mengxr/Lewuathe-modify-javadoc-setting and squashes the following commits:

184609a [Xiangrui Meng] merge spark.ml and spark.mllib into the same group in javadoc
f7535e6 [lewuathe] [SPARK-4685] Update JavaDoc settings to include spark.ml and all spark.mllib subpackages in the right sections
[SQL] Minor: Avoid calling Seq#size in a loop

Just found this instance while doing some jstack-based profiling of a Spark SQL job. It is very unlikely that this is causing much of a perf issue anywhere, but it is unnecessarily suboptimal.

Author: Aaron Davidson <aaron@databricks.com>

Closes #3593 from aarondav/seq-opt and squashes the following commits:

962cdfc [Aaron Davidson] [SQL] Minor: Avoid calling Seq#size in a loop
[docs] Fix outdated comment in tuning guide

When you use the SPARK_JAVA_OPTS env variable, Spark complains:

```
SPARK_JAVA_OPTS was detected (set to ' -verbose:gc -XX:+PrintGCDetails -XX:+PrintGCTimeStamps ').
This is deprecated in Spark 1.0+.

Please instead use:
 - ./spark-submit with conf/spark-defaults.conf to set defaults for an application
 - ./spark-submit with --driver-java-options to set -X options for a driver
 - spark.executor.extraJavaOptions to set -X options for executors
 - SPARK_DAEMON_JAVA_OPTS to set java options for standalone daemons (master or worker)
```

This updates the docs to redirect the user to the relevant part of the configuration docs.

CC: mengxr  but please CC someone else as needed

Author: Joseph K. Bradley <joseph@databricks.com>

Closes #3592 from jkbradley/tuning-doc and squashes the following commits:

0760ce1 [Joseph K. Bradley] fixed outdated comment in tuning guide
[SPARK-4575] [mllib] [docs] spark.ml pipelines doc + bug fixes

Documentation:
* Added ml-guide.md, linked from mllib-guide.md
* Updated mllib-guide.md with small section pointing to ml-guide.md

Examples:
* CrossValidatorExample
* SimpleParamsExample
* (I copied these + the SimpleTextClassificationPipeline example into the ml-guide.md)

Bug fixes:
* PipelineModel: did not use ParamMaps correctly
* UnaryTransformer: issues with TypeTag serialization (Thanks to mengxr for that fix!)

CC: mengxr shivaram  etrain  Documentation for Pipelines: I know the docs are not complete, but the goal is to have enough to let interested people get started using spark.ml and to add more docs once the package is more established/complete.

Author: Joseph K. Bradley <joseph@databricks.com>
Author: jkbradley <joseph.kurata.bradley@gmail.com>
Author: Xiangrui Meng <meng@databricks.com>

Closes #3588 from jkbradley/ml-package-docs and squashes the following commits:

d393b5c [Joseph K. Bradley] fixed bug in Pipeline (typo from last commit).  updated examples for CV and Params for spark.ml
c38469c [Joseph K. Bradley] Updated ml-guide with CV examples
99f88c2 [Joseph K. Bradley] Fixed bug in PipelineModel.transform* with usage of params.  Updated CrossValidatorExample to use more training examples so it is less likely to get a 0-size fold.
ea34dc6 [jkbradley] Merge pull request #4 from mengxr/ml-package-docs
3b83ec0 [Xiangrui Meng] replace TypeTag with explicit datatype
41ad9b1 [Joseph K. Bradley] Added examples for spark.ml: SimpleParamsExample + Java version, CrossValidatorExample + Java version.  CrossValidatorExample not working yet.  Added programming guide for spark.ml, but need to add CrossValidatorExample to it once CrossValidatorExample works.
[FIX][DOC] Fix broken links in ml-guide.md

and some minor changes in ScalaDoc.

Author: Xiangrui Meng <meng@databricks.com>

Closes #3601 from mengxr/SPARK-4575-fix and squashes the following commits:

c559768 [Xiangrui Meng] minor code update
ce94da8 [Xiangrui Meng] Java Bean -> JavaBean
0b5c182 [Xiangrui Meng] fix links in ml-guide
[SPARK-4683][SQL] Add a beeline.cmd to run on Windows

Tested locally with a Win7 VM. Connected to a Spark SQL Thrift server instance running on Mac OS X with the following command line:

```
bin\beeline.cmd -u jdbc:hive2://10.0.2.2:10000 -n lian
```

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Author: Cheng Lian <lian@databricks.com>

Closes #3599 from liancheng/beeline.cmd and squashes the following commits:

79092e7 [Cheng Lian] Windows script for BeeLine
[SPARK-4253] Ignore spark.driver.host in yarn-cluster and standalone-cluster modes

In yarn-cluster and standalone-cluster modes, we don't know where driver will run until it is launched.  If the `spark.driver.host` property is set on the submitting machine and propagated to the driver through SparkConf then this will lead to errors when the driver launches.

This patch fixes this issue by dropping the `spark.driver.host` property in SparkSubmit when running in a cluster deploy mode.

Author: WangTaoTheTonic <barneystinson@aliyun.com>
Author: WangTao <barneystinson@aliyun.com>

Closes #3112 from WangTaoTheTonic/SPARK4253 and squashes the following commits:

ed1a25c [WangTaoTheTonic] revert unrelated formatting issue
02c4e49 [WangTao] add comment
32a3f3f [WangTaoTheTonic] ingore it in SparkSubmit instead of SparkContext
667cf24 [WangTaoTheTonic] document fix
ff8d5f7 [WangTaoTheTonic] also ignore it in standalone cluster mode
2286e6b [WangTao] ignore spark.driver.host in yarn-cluster mode
[HOTFIX] Fixing two issues with the release script.

1. The version replacement was still producing some false changes.
2. Uploads to the staging repo specifically.

Author: Patrick Wendell <pwendell@gmail.com>

Closes #3608 from pwendell/release-script and squashes the following commits:

3c63294 [Patrick Wendell] Fixing two issues with the release script:
[SPARK-4745] Fix get_existing_cluster() function with multiple security groups

The current get_existing_cluster() function would only find an instance belonged to a cluster if the instance's security groups == cluster_name + "-master" (or "-slaves"). This fix allows for multiple security groups by checking if the cluster_name + "-master" security group is in the list of groups for a particular instance.

Author: alexdebrie <alexdebrie1@gmail.com>

Closes #3596 from alexdebrie/master and squashes the following commits:

9d51232 [alexdebrie] Fix get_existing_cluster() function with multiple security groups
[SPARK-4459] Change groupBy type parameter from K to U

Please see https://issues.apache.org/jira/browse/SPARK-4459

Author: Saldanha <saldaal1@phusca-l24858.wlan.na.novartis.net>

Closes #3327 from alokito/master and squashes the following commits:

54b1095 [Saldanha] [SPARK-4459] changed type parameter for keyBy from K to U
d5f73c3 [Saldanha] [SPARK-4459] added keyBy test
316ad77 [Saldanha] SPARK-4459 changed type parameter for groupBy from K to U.
62ddd4b [Saldanha] SPARK-4459 added failing unit test
[SPARK-4652][DOCS] Add docs about spark-git-repo option

There might be some cases when WIPS spark version need to be run
on EC2 cluster. In order to setup this type of cluster more easily,
add --spark-git-repo option description to ec2 documentation.

Author: lewuathe <lewuathe@me.com>
Author: Josh Rosen <joshrosen@databricks.com>

Closes #3513 from Lewuathe/doc-for-development-spark-cluster and squashes the following commits:

6dae8ee [lewuathe] Wrap consistent with other descriptions
cfaf9be [lewuathe] Add docs about spark-git-repo option

(Editing / cleanup by Josh Rosen)
[SPARK-4397] Move object RDD to the front of RDD.scala.

I ran into multiple cases that SBT/Scala compiler was confused by the implicits in continuous compilation mode. Adding explicit return types fixes the problem.

Author: Reynold Xin <rxin@databricks.com>

Closes #3580 from rxin/rdd-implicit and squashes the following commits:

ee32fcd [Reynold Xin] Move object RDD to the end of the file.
b8562c9 [Reynold Xin] Merge branch 'master' of github.com:apache/spark into rdd-implicit
d4e9f85 [Reynold Xin] Code review.
a836a37 [Reynold Xin] Move object RDD to the front of RDD.scala.
[SPARK-4421] Wrong link in spark-standalone.html

Modified the link of building Spark.

Author: Masayoshi TSUZUKI <tsudukim@oss.nttdata.co.jp>

Closes #3279 from tsudukim/feature/SPARK-4421 and squashes the following commits:

56e31c1 [Masayoshi TSUZUKI] Modified the link of building Spark.
Fix typo in Spark SQL docs.

Author: Andy Konwinski <andykonwinski@gmail.com>

Closes #3611 from andyk/patch-3 and squashes the following commits:

7bab333 [Andy Konwinski] Fix typo in Spark SQL docs.
[SPARK-4464] Description about configuration options need to be modified in docs.

Added description about -h and -host.
Modified description about -i and -ip which are now deprecated.
Added description about --properties-file.

Author: Masayoshi TSUZUKI <tsudukim@oss.nttdata.co.jp>

Closes #3329 from tsudukim/feature/SPARK-4464 and squashes the following commits:

6c07caf [Masayoshi TSUZUKI] [SPARK-4464] Description about configuration options need to be modified in docs.