Text tracks api

I think I understand more. EventEmitter is being used to create mock DOM elements.

Since this complexity is only added because we're trying to use it as a mock element, could we create a MockElement class that
- extends event emitter
- adds the addEventListener alias
- replaces addEventListener with a noop while vjs.on() is running

I would say just rename EventEmitter, but I like the idea of having Component extend event emitter at some point.