Make more thread safe
Merge tag '0.13' into develop

v0.13
Updated homepage URL
Merge branch 'master' of github.com:ReactiveX/RxPY
Merge branch 'master' into develop
Merge branch 'develop' into feature/threads
Cleanup and docstring changes
Made ScheduledObserver thread safe
Added some changes
Rename from select to map
Removed un-needed initialization
Added needed initializations
Pairwise now emits a tuple instead of a list
String the value in case it's a tuple
Implements more of the locking protocol
Cleanup
Added locking
Merge branch 'develop' of github.com:ReactiveX/RxPY into develop
Removed dependency on six
Removed more dependencies on six