Cheats and keys updates

This was originally a pull request to fix a typo in the materials cheat but I got sidetracked so it's a bit more than that.

* Update cheats to fix typo (which @bucketh3ad has now fixed)
* Update cheats to include all materials/consumables/potions
* Change the Lost DVD from a material to a key, locking the door in frozen cave & added in the functionality of keys giving you customized messages
* get master key from the cheat screen