This is just in case someone actually tries to dump in C_START/C_END and "add" colormaps using them, not that they would ever be used currently anyway.
Used instead of pLocalPalette when attempting to determine objective truths, such as "the colours of this gif without color profile modification" and "what indicies should this colormap remap to".
Also, made f_wipe.c's paldiv only get calculated once.
Add a vertical flip variant for the translucent column drawer.
Translucency is now properly distributed: 0.00 leads to no render at all, 0.1 to TRANS10, ..., 0.9 to TRANS90, 1 to regular column drawer.
Some texture-related fixes
Bugs fixed in this branch:
* upper/lower/middle textures with non-existent texture ids being capable of crashing the game. For instance, RVZ1 has colormap codes on non-colormap linedefs, which causes them to wind up with invalid texture ids because of how the game tries to interpret lower/upper textures with "#" followed by characters on normal linedefs. Fortunately these "textures" are normally not visible anyway (since they're all in control sectors) unless they are swapped with in-level textures by some crazy Lua script of some sort...
* animated single-patch textures with holes displaying garbage on first viewing (see this thread: https://mb.srb2.org/showthread.php?t=42195)
* the heights of the lighting (shadows or colormapping) from water/translucent/shadowcasting/etc FOFs become messed up when displayed on repeated midtextures.
See merge request !144
*Added FLIPX/FLIPY support for multi-patch textures and single-patch textures without holes
*Added FLIPY support for single-patch textures with holes; I'll sort FLIPX support out later