[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