Emit ckeditor.ready event instead of broadcasting and send instance

It seems to me (and certainly is so in my case) that it's more useful to `$emit` the ckeditor.ready event rather than `$broadcast` it so parent scopes hear about it instead of child scopes. For example, it allows me to use `ng-if` and still hear the event.

Also, it's useful to send a reference to the instance with the event.