More helpful error messages

See merge request !243

Smoother MD2 interpolation

See merge request STJr/SRB2!224

Fixed MD2 models not loading correctly on Linux

Lua exploit fix

See merge request !259

Disable admin password by default

Minor net command fixes

Multiplayer menu playername fix

See merge request !256

fix the multiplayer menu not allowing the full max length for player names unlike the "name" console command

Correct C FixedMul() off-by-one errors

See merge request STJr/SRB2!245

F12 fix

See merge request STJr/SRB2!250

Don't increment totalplaytime if a demo is playing.

See merge request !241

OpenGL: Map Specific Palette Fix

See merge request STJr/SRB2!247

OpenGL: Very large map rendering issue fixed

See merge request STJr/SRB2!249

Fix console typo

See merge request STJr/SRB2!246

OpenGL: Fix FF_FULLBRIGHT not working in sectors with multiple light levels

See merge request STJr/SRB2!244

FOF sector special fixes

See merge request !242

This should hopefully kill the F12 getting stuck issue once and for all.

Move old fix for too large maps having rendering issues from R_CheckBBox to OpenGL's HWR_CheckBBox
From what I know, this effects at least Aerial Garden and Seraphic Skylands

Stop Each Time trigger linedefs and object-carrying scrollers from doing anything with FOFs without FF_EXISTS

The FixedMul() C implementation would produce off by one results,
causing constant desyncs on 64 bit builds and builds without an
ASM implementation of the function.

This is fixed by shifting instead of dividing, possibly avoiding
rounding errors.

This makes OpenGL stop using a specific function that doesn't really do anything for it anymore. It looks like it was used for a hack that would change the colour of polygons for the flashpal equivalent in DOOM.
I made it so ST_DoPaletteStuff doesn't set the flashpal in OpenGL as it already does its own hacky overlay and doing that would cause all the textures to be flushed more mid-level, it could be enabled for more correct flashpals, but they still wouldn't effect fog or lighting.
This means the palette will be set when going to the title screen, and twice when starting a map, (causing the OpenGL cached textures to also be flushed at those times)