Renamed Classes

Renamed MobObelisk to MobMonolith. Renamed LimboSkyProvider and
PocketProvider to have Xs at the ends of their names. This is temporary
so that I can change the name's capitalization. Windows considers the
names the same because it's file naming is case insensitive.
Finished Renaming Classes

Removed the Xs from the ends of LimboSkyProvider and PocketProvider. Now
their names are properly capitalized.