Updated EventDispatcher

Updated web audio calls to support new APIs

Signed-off-by: Lanny McNie <lanny@gskinner.com>
Updated EventDispatcher

* New EventDispatcher, supports bubbling
* Added Event.js, updated generic events to Event objects
* Removed deprecated onEvent callbacks
* Updated docs. Added more cross links
* Updated build script to include Event.js

Signed-off-by: Lanny McNie <lanny@gskinner.com>