-- ActionVisualization and ActionFX base classes added.
-- MeleeActionFX logic added, and some logic to only play the hit react if the target is still in range.
-- folded "Level" into ActionRequestData. (The server takes care to sanitize the field if a request comes from the client).
-- hit detection logic has moved to a shared ActionUtils class. I wound up not making use of it in this change, but I still think it's likely this logic will need to be shared between server and client, or between different actions on the server. (It will also likely grow more complex).
-- Added a BrainEnabled switch. This is mainly intended for debugging, although it's possible it could be part of a "Stun" effect. Switch it to false to turn monsters into helpless punching bags.
-- split off some of Action into a shared ActionBase class. This is because Action and ActionFX ended up sharing several concepts.
-- Changed server-duration to match the animat...