Add a better event handling system using core.async

[Ryan Haney]

I need a better event system. The main reason for this is similar to the reason for a better network system. In other words, the fact that as it is now, it would be very difficult to automatically add event functions. With a new system, I should be able to just subscribe to each event, allowing the implementation to be created automatically and somewhat dynamically.

I'm going to switch to this now, as entities and entity properties are bugging up with the sync systems. More specifically, when trying to do a full sync with those entities (upon reloading a world, for example), they sometimes aren't fully loaded, causing some very unstable behavior. Being able to subscribe to events under the hood would allow this in addition to other goodies, such as being able to register Extended Entity Properties without having to create an event handler for it.

[Ryan Haney]

Closing because Minecraft Forge's event system is retarded. This is sadly impossible.