Large changes from latest prototype.
No more entityType or actorType. Clean up bridge.cfg to match this.
Rewrite entity management to be smaller and easier to reuse.
Simplify animated entity creation.
Since entity management is class based, no need for actor interface anymore.
Reorganize some older messy packages (io, particle)
Improved boundingBox functionality.
Remove redundant functionality from HitTest
Shorter entity management names.