Make TakeUntil obey Rx contract
Ignore furthur messages after entering terminate state
Merge pull request #1657 from zsxwing/fix-onErrorReturn

Ignore furthur messages after entering terminate state
Error Handling Unsubscribe and Terminal State
Merge pull request #1669 from benjchristensen/unsubscribe-in-error-handlers

Error Handling Unsubscribe and Terminal State
Merge pull request #1656 from zsxwing/fix-takeUntil

Make TakeUntil obey Rx contract
[Gradle Release Plugin] - pre tag commit:  '0.20.4'.
[Gradle Release Plugin] - new version commit:  '0.20.5-SNAPSHOT'.
0.20.4
Merge branch '0.20.x' of https://github.com/ReactiveX/RxJava into refcount-fix