Added lib/unsupported.js for unsupported items

WARNING: Currently calls TileEntities unsupported. IF YOU IMPLEMENT THEM, PLEASE CHANGE THIS!!
New features:
Unsupported.items (array of unsupported items - does not include those unsupported items >= 256)
Unsupported.checkForBlock(block id) Returns false if a block is unsupported, a block id if it is or is placed under a different id than given.