complete or remove event emitter

[AlmirKadric]

Right now we have an event emitter, however this is not quite the way C# handles events.
They use a predefined delegate per event, thus each event is explicit.

Either we need to move the entire sdk to do this, or we need to complete the event emitter to be a fully fledged event emitter class.

Missing event emitter functions:

• listenerCount(eventName)
• off(eventName, hander) (aka: removeListener)
• removeAllListeners(optional eventName)

[stelcheck]

@nullorvoid comments or suggestions welcome.