Add constness to AnimatedSprite::render

Should have been const.
Made Door renderable via AnimatedSprite
Parsing animation/image for Doors in MapLoader
Added updateDoors() to GamePlayState
Fixed door rendering in MapRenderer
Made "entrance" solid in test map 4, room 1
More tweaks to test map 4
Fixed wrong door updates in GamePlayState
Adding statefulness to doors
Added more realistic doors
Using default syncgroup for door animations