Animation emitters have different tenses

[samreid]

From #11

The emitters are:

    this.startEmitter = new Emitter();
    this.beginEmitter = new Emitter();
    this.finishEmitter = new Emitter();
    this.stopEmitter = new Emitter();
    this.endedEmitter = new Emitter();
    this.updateEmitter = new Emitter();

Perhaps we should rename endedEmitter => endEmitter unless there is a good reason for the inconsistency?

[pixelzoom]

+1 to rename endedEmitter => endEmitter.