Refactor and cleanup
Updated TODO
Updated DungeonBlocks and references to its rooms
Enhanced SetExits()
Refactor, fixing the branch bug and adding more comments.
Updated TODO
Updated dependencies
Abstracted materials into their IDs using materials from pymclevel, fixed lighting bug
Update README.md
Crop demo image
Corrected getmail permissions
Moved preview pictures into their own folder
Switched all instances of range to xrange -- we wanted iterators, not lists
Trimmed imports
Refactored getmail to reduce indentation (previously had 7 levels of indentation!)