BufferWithSize with Backpressure Support
Handle overflow
Adding backpressure to OnSubscribeRedo
SwitchOnNext with backpressure support
More consistent hooks for scheduler plugins.  This is a rework of #1514.
* Deprecated RxJavaDefaultSchedulers and RxJavaDefaultSchedulersDefault (I think these names are confusing)
* Added RxJavaSchedulersHook
** Ability to override entire schedulers from scratch
** Ability to decorate Action0 before submission to Scheduler
TakeLastTimed with backpressure support
Fix errors in Completeness.scala and also improve it
Add a blank line to fix the bullet points issue
Merge pull request #1559 from mattrjacobs/scheduler-plugin

More consistent hooks for scheduler plugins.  This is a rework of #1514.
Merge pull request #1548 from stealthcode/BPRedo

Adding backpressure to OnSubscribeRedo
Merge pull request #1564 from zsxwing/rxscala-completeness

RxScala: Fix errors in Completeness.scala and also improve it
Merge pull request #1562 from zsxwing/backpressure-takeLastTimed

TakeLastTimed with backpressure support
Merge pull request #1557 from zsxwing/backpressure-switch

SwitchOnNext with backpressure support
Merge pull request #1507 from zsxwing/backpressure-bufferWithSize

BufferWithSize with Backpressure Support
Fixing Kotlin Defer

Broke this with https://github.com/Netflix/RxJava/pull/1561
Merge pull request #1565 from benjchristensen/kotlin-defer

Fixing Kotlin Defer
groupBy with element selector

Fixes https://github.com/Netflix/RxJava/issues/1554
Merge pull request #1567 from benjchristensen/groupBy-selector

groupBy with element selector
Compose/Transformer

See https://github.com/Netflix/RxJava/issues/1416 for discussion that led to this.

This does not have co/contra-variance which needs to be figured out.
Merge pull request #1568 from benjchristensen/compose-transformer

Compose/Transformer