Another big update of entities.def. Looking great in Radiant.
Updated gehenna.map to replace all func_walls with func_group, fix the func_door_rotating, and fix a lava brush.
Updated Gehenna with fixed oil drill, 40 or so less BSP entities, and fixed microbrushes.
Updated Stress Fractures with fixed brush, texture alignment bugs and new intermission point (previous intermission was buried inside wall). Also make the icey floors SURF_SLICK for fun.