Draft group by implementation
Concurrency improvements
Updated Observable API
copyright update
Removed static methods delegations
Merge branch 'groupby' of git://github.com/mairbek/RxJava into groupBy-review
Refactor to eliminate need of delegate methods for GroupedObservable
Move GroupedObservable to rx.observables
Merge pull request #179 from benjchristensen/groupBy-review

Operator GroupBy Pull Request - Review and Refactor