Merged together the different changes we had made to Transdimensional
Trapdoors. Cleaned up the rendering and tile entity code a bit, it
should be a little more understandable now.
Got the Transdimensional Trapdoor working again. Renamed the file to
TransTrapdoor and trimmed off unnecessary code - BlockTrapDoor
implements a lot of the necessary logic. Implemented IDimDoor for
clarity.