The Hell v1.68

I think this version will be the last for quite a while. It includes some changes that were planned long ago.
Changelog (1.67t RC2 -> 1.68): + Added 8 new palettes for Catacombs: 76, 77, 78, 79, 80, 81, 82, 83; + Added 8 new palettes for Caves: 76, 77, 78, 79, 80, 81, 82, 83; + Added 9 new palettes for Hell: 76, 77, 78, 79, 80, 81, 82, 83, 84;