Added cactus to sand island
Added bedrock island, not at final location
Added pymclevel to the .gitignore so I can have a symlink
Refactored and added chest code.  Backed out crash-causing code
Use markup for the unordered list of prerequisites
Added tree, target nether portal, mushrooms, and nether wart
Got items in chests working (mostly)
Made portals and portal island work