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
Merge pull request #1286 from davidmoten/operator-to-onsubscribe

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