Added an emit method to EventEmitter, and also added chaining.

Added Chaining to the EventEmitter class (and therefore, batCanvas,
inheritance is awesome!)
Also added an emit method to EventEmitter
So now you can do this: new BatCanvas("canvas").on("draw",
function(){/*Do stuff*/}).on("draw", function(){/*morestuff*/}).start();
Also should there be a way for emit in the draw event by default use
context (don't know how i'd do that, but just a thought)