Removing rx.scala from EventStreamListeners. I don't like this, too much
inheritance
I prefer using rx scala to too much inheritance

Although it does introduce some complexity if you are not used to rx, I
think it's much cleaner code to use observers instead of inheritance,
we'll keep it like this in theses classes for now
Refactored class names a bit
Looks like rx-scala is a good idea after all
Deleted some todos