Dispatcher

Dispatcher is an incredibly simple little component/system that makes it possible to invoke code on the main thread from other threads. Usage is simple:

1. Add the Dispatcher component to an object in your scene.
2. Call the static methods InvokeAsync(Action) or Invoke(Action) to run actions on the main thread.

InvokeAsync will queue up the action and return immediately so your thread can keep on going. Invoke, on the other hand, will block the calling thread until the action has run. In both cases the Dispatcher will immediately invoke the action if the calling thread is the main thread (this also prevents deadlocks in case you call Invoke from the main thread).

InvokeAsync will not generate any garbage because it simply queues up the action. Invoke currently allocates a new lambda that will invoke the given argument and set a boolean to know when to return from the method. This could be fixed later, but most places are likely fine using InvokeAsync.