CombineLatest fix
Moved onError, onCompleted and cancel.unsubscribed outside the lock
Merge branch 'CombineLatestFix' of github.com:akarnokd/RxJava into combine-latest
Manual Merge of Pull #616

Manual merge of https://github.com/Netflix/RxJava/pull/616

- remove use of SingleAssignmentSubscription
- suppress warnings
Merge pull request #708 from benjchristensen/combine-latest

Combine latest fix