TODO:
- update world file when chat commands are used
- update inventories when items are replaced:
	- creative
	- storage (chests, etc.)
- add LBM when removing an item if it is a node
- add "radius" option for pencil or "xlen", "ylen", & "zlen" options
- add "xrotate" & "zrorate" modes for pencil
- fix pencil "write" mode when pointing to side of node (node gets placed below)