Replace all {S,W,B}FALL textures in the levels with their animated
equivalents, and remove {S,W,B}FALL from textures.cfg.
The {S,W,B}FALL were leftovers from when Freedoom had the goal of
being Boom-compatible instead of vanilla-compatible.
Also, rebuild these levels' nodes and reject tables with ZenNode.
- Remove inaccessible secrets: teleporter pad on west side of map, box
behind marble face by rocket launcher
- Remove unneeded interiors: a couple of pillars, and a crate, had
backsectors with floor==ceiling
- Allow shortcut door from blue key warehouse back to main area to be
opened. It looks like there was a button to open several doors, with
tag 1, but the switch was apparently removed and replaced with a key.
- Clean up some unnecessary linedef and sector tags
- Remove or redistribute some of the incredible excess of ammunition.