Enlarged dungeon
A lot of useful refactoring
Updated TODO
Refactored current_xxx_number to xxx_num
Updated TODO
Updated DungeonBlocks and references to its rooms
Enhanced SetExits()
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
Trimmed imports
Refactored getmail to reduce indentation (previously had 7 levels of indentation!)