GameZones, PhysicalMaps, and Doors

GameZones are going to be the equivalent of levels in the game. It is a
region that handles itself, adds its objects to the PhysicsEngine and
Display and cleans everything up when its done. Currently, It takes
control but the mechanics of how the end product will work are
undetermined.

CollisionLayers/CollisionOrders/DisplayLayers are now finite
enumerations that sort themselves accordingly. I think this is easier
than numbers because I can associate a name with a layer and change
their order from one place.

Doors will link GameZones together. Each door has a destination GameZone
and a Door ID in that GameZone that it attaches to. Doors do not have to
link exclusively (leaves room for puzzles)

PhysicalMaps are maps built of surfaces rather than DisplayObjects.
PhysicalMaps can Apply to any CollisionLayer. Let level production
begin.