[1.2.0] Update functions to interfaces.
Upgrade to 0.17.0-RC1. Refactor and build
WIP change to ReplaySubject instead of maintaining observaers
Fix constructors for Java Promises
Revert back to rx functions, but do not expose rx observable
Up rxjava version
Remove defer(), add constructor for Observable
Merge branch 'master' of github.com:darylteo/rxjava-promises