Part of #39: loads of map changes

- Added background as tiles, not a repeating image
- Audio is a map property
- Deleted dead codez
Generalized code more; indoor map works now.

- Background is now just a simple image name
- Perimeter is now just a simple image name
- Removed unnecessary entities
Fix up tests as part of recent fixes.
Part of #39: Door + Refactoring for Game

- Created door entity with transition method
- Put it in the world map
- Moved tons of Scene code into the game for map loading
Resolved #39: Transitions!

- Fix infinite loop on transitions
- Destroy old objects so we get a clean map
#39: transitioning doesn't respect destination

- Fixed issue with mangling of `player.gridY`
- Properly transition to target coordinates
- Added NPC in house