added support for alternate (non main) looper

key changes are in EventBus.java
* Added constructor EventBus(Looper) -- the provided looper's thread becomes the "main thread" -- an unfortunate naming convention clash with the official 'main' thread, possibly.
* Added function isMainThread() 

Events are posted to onEventMainThread() although the thread isn't that of the main looper; rather it is invoked on the provided looper.

Other changes are cosmetic (for machine local builds)