Version 0.18.4
Rename classes starting with Operator that are actually OnSubscribe implementations to start with OnSubscribe
Merge branch 'master' of https://github.com/Netflix/RxJava into operator-to-onsubscribe
fix GroupBy and GroupByUntil which are actually Operators
Ensure StringObservable.from() does not perform read when already unsubscribed because read could block
adding javadocs to ChainedSubscription methods
Merge branch 'master' of https://github.com/Netflix/RxJava into docs
Merge pull request #1288 from davidmoten/string-from-bytes

Ensure StringObservable.from() does not perform unnecessary read
Merge pull request #1286 from davidmoten/operator-to-onsubscribe

Rename some Operator* classes to OnSubscribe* as per #1270