Allow creating observables from `AbstractButton`s.
Refactored implementation out from SwingObservable, as there will
probably be lots more methods in the long run.
Added some api documentation.
Merge branch 'SwingScheduler' into swing
Moved Swing observables to new subfolder `rxjava-contrib` after merge.
Added key events as source for Swing observables.
Added filtering for key codes.
Merge branch 'master' into swing
Merge branch 'improved-scan' into swing
Added observable for all currently pressed keys
Added basic mouse event observables.
added a missing license header
moved SwingObservable into the rx.observables package
Merge pull request #262 from jmhofer/swing

A few basic Swing observables