Initial regionEvents pass

Fixes #1183


## TODO / Ideas
  * [ ] handle method def of regionEvent
  * [ ] handle string based regionEvent
  * [ ] handle regionEvents via options
  * [ ] handle `all` based registration
  * [ ] ensure we are not introducing memory leaks
  * [ ] know which region is emitting the event
  * [ ] addRegionEvent
  * [ ] addRegionEvents
  * [ ] removeRegionEvent
  * [ ] removeRegionEvents
do we know which view this is? if not maybe we do something like `_.partial(this.onViewEvent, view)`