ALS implicit: added missing parameter alpha in doc string

Author: Felix Maximilian Möller <felixmaximilian.moeller@immobilienscout24.de>

Closes #3343 from felixmaximilian/fix-documentation and squashes the following commits:

43dcdfb [Felix Maximilian Möller] Removed the information about the switch implicitPrefs. The parameter implicitPrefs cannot be set in this context because it is inherent true when calling the trainImplicit method.
7d172ba [Felix Maximilian Möller] added missing parameter alpha in doc string.
[SPARK-4435] [MLlib] [PySpark] improve classification

This PR add setThrehold() and clearThreshold() for LogisticRegressionModel and SVMModel, also support RDD of vector in LogisticRegressionModel.predict(), SVNModel.predict() and NaiveBayes.predict()

Author: Davies Liu <davies@databricks.com>

Closes #3305 from davies/setThreshold and squashes the following commits:

d0b835f [Davies Liu] Merge branch 'master' of github.com:apache/spark into setThreshold
e4acd76 [Davies Liu] address comments
2231a5f [Davies Liu] bugfix
7bd9009 [Davies Liu] address comments
0b0a8a7 [Davies Liu] address comments
c1e5573 [Davies Liu] improve classification
[SPARK-4396] allow lookup by index in Python's Rating

In PySpark, ALS can take an RDD of (user, product, rating) tuples as input. However, model.predict outputs an RDD of Rating. So on the input side, users can use r[0], r[1], r[2], while on the output side, users have to use r.user, r.product, r.rating. We should allow lookup by index in Rating by making Rating a namedtuple.

davies

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Author: Xiangrui Meng <meng@databricks.com>

Closes #3261 from mengxr/SPARK-4396 and squashes the following commits:

543aef0 [Xiangrui Meng] use named tuple to implement ALS
0b61bae [Xiangrui Meng] Merge remote-tracking branch 'apache/master' into SPARK-4396
d3bd7d4 [Xiangrui Meng] allow lookup by index in Python's Rating
[SQL] Support partitioned parquet tables that have the key in both the directory and the file

Author: Michael Armbrust <michael@databricks.com>

Closes #3272 from marmbrus/keyInPartitionedTable and squashes the following commits:

447f08c [Michael Armbrust] Support partitioned parquet tables that have the key in both the directory and the file
[SPARK-4075][SPARK-4434] Fix the URI validation logic for Application Jar name.

This PR adds a regression test for SPARK-4434.

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

Closes #3326 from sarutak/add-triple-slash-testcase and squashes the following commits:

82bc9cc [Kousuke Saruta] Fixed wrong grammar in comment
9149027 [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into add-triple-slash-testcase
c1c80ca [Kousuke Saruta] Fixed style
4f30210 [Kousuke Saruta] Modified comments
9e09da2 [Kousuke Saruta] Fixed URI validation for jar file
d4b99ef [Kousuke Saruta] [SPARK-4075] [Deploy] Jar url validation is not enough for Jar file
ac79906 [Kousuke Saruta] Merge branch 'master' of git://git.apache.org/spark into add-triple-slash-testcase
6d4f47e [Kousuke Saruta] Added a test case as a regression check for SPARK-4434
Merge branch 'master' of http://git-wip-us.apache.org/repos/asf/spark into lbfgs

Conflicts:
	python/pyspark/mllib/classification.py