Health rendering has been moved into an entity animation.
Added utility to help pick out tiles.
Modified Wood Wall to be double-lined.
Each entity now has a unique tile instance.  Slows load time down a bit,
but allows tiles to uniquely modify their image.
Touch a Wooden Door to open it.
Villages now generate simple wooden houses (a room with a door).
Torches now have a dark background to differentiate them from the floor.
cacheEntitiesInRange is now public, to allow the door to update the
viewable region.
Doors now update the viewable area when they change state.
Houses contain torhces, and no longer intersect.