Completed Implementation of Dungeon Packs

Completed the implementation of dungeon packs and configurable dungeon generation. Please see the commits for particulars on what was changed. The only noteworthy change is that the list of bundled dungeons is now stored separately for each pack we have. The list would go in "/schematics", although that's not enforced by the code and they could go anywhere. We only have one at the moment, "ruins.txt", for the Ruins pack. The file doesn't need to share the same name as the pack at all, it's just a good convention.