Made chainable. Added node-style aliases.

Just let me say, I’m a big fan of this module; it’s been my go-to for browser events for quite a while now (Love me some Crollian mixins!). So I’ve done two things.

1. I’ve added return statements to the mixin methods so that listeners can be attached in a chainable way. ie.
``` js
dog
  .on('bark', function() {})
  .on('sit', function() {})
```

2. I’ve added some additional aliases to the mixin methods to mirror node’s [EventEmitter (http://nodejs.org/api/events.html).

I minified my changes as well, but I used uglify and I think you might be using something else, so perhaps that file can be ignored. But let me know if you’d like anything changed, and thanks again :)