Version 2.4.0

Version 2.4.0-RC3

Version 2.4.0-beta.1

Version 2.4.0-beta

Update build.gradle

don't deprecate, just remove and do a breaking release.

changed my mind, we won't deprecate these

Remove Java 8 targeting

combineLatest extensions for Observable and Flowable (ReactiveX#116)

* combineLatest extensions for Observable and Flowable

* jdk8

Merge branch 'sam-adapters' into 2.x