DEHACKED: un-name DM31/DM32, leaving them as a placeholders

The Wolfenstein 3D homages have been removed, and these names were
also based on Wolf3D.  Removing them to make it clearer that the
levels need new names.
DEHACKED: Name a whole bunch of Phase 2 levels

These come from Voltcom9 and JudgeDeadd on the Doomworld Forums, thanks!