HOTFIX: Disabling failing block manager test
[SPARK-4494][mllib] IDFModel.transform() add support for single vector

I improved `IDFModel.transform` to allow using a single vector.

[[SPARK-4494] IDFModel.transform() add support for single vector - ASF JIRA](https://issues.apache.org/jira/browse/SPARK-4494)

Author: Yuu ISHIKAWA <yuu.ishikawa@gmail.com>

Closes #3603 from yu-iskw/idf and squashes the following commits:

256ff3d [Yuu ISHIKAWA] Fix typo
a3bf566 [Yuu ISHIKAWA] - Fix typo - Optimize import order - Aggregate the assertion tests - Modify `IDFModel.transform` API for pyspark
d25e49b [Yuu ISHIKAWA] Add the implementation of `IDFModel.transform` for a term frequency vector
[SPARK-4826] Fix generation of temp file names in WAL tests

This PR should fix SPARK-4826, an issue where a bug in how we generate temp. file names was causing spurious test failures in the write ahead log suites.

Closes #3695.
Closes #3701.

Author: Josh Rosen <joshrosen@databricks.com>

Closes #3704 from JoshRosen/SPARK-4826 and squashes the following commits:

f2307f5 [Josh Rosen] Use Spark Utils class for directory creation/deletion
a693ddb [Josh Rosen] remove unused Random import
b275e41 [Josh Rosen] Move creation of temp. dir to beforeEach/afterEach.
9362919 [Josh Rosen] [SPARK-4826] Fix bug in generation of temp file names. in WAL suites.
86c1944 [Josh Rosen] Revert "HOTFIX: Disabling failing block manager test"
[SPARK-1037] The name of findTaskFromList & findTask in TaskSetManager.scala is confusing

Hi all - I've renamed the methods referenced in this JIRA to clarify that they modify the provided arrays (find vs. deque).

Author: Ilya Ganelin <ilya.ganelin@capitalone.com>

Closes #3665 from ilganeli/SPARK-1037B and squashes the following commits:

64c177c [Ilya Ganelin] Renamed deque to dequeue
f27d85e [Ilya Ganelin] Renamed private methods to clarify that they modify the provided parameters
683482a [Ilya Ganelin] Renamed private methods to clarify that they modify the provided parameters
[SPARK-4668] Fix some documentation typos.

Author: Ryan Williams <ryan.blake.williams@gmail.com>

Closes #3523 from ryan-williams/tweaks and squashes the following commits:

d2eddaa [Ryan Williams] code review feedback
ce27fc1 [Ryan Williams] CoGroupedRDD comment nit
c6cfad9 [Ryan Williams] remove unnecessary if statement
b74ea35 [Ryan Williams] comment fix
b0221f0 [Ryan Williams] fix a gendered pronoun
c71ffed [Ryan Williams] use names on a few boolean parameters
89954aa [Ryan Williams] clarify some comments in {Security,Shuffle}Manager
e465dac [Ryan Williams] Saved building-spark.md with Dillinger.io
83e8358 [Ryan Williams] fix pom.xml typo
dc4662b [Ryan Williams] typo fixes in tuning.md, configuration.md