R_InitExtraColormaps fix
This fixes the `R_InitExtraColormaps` function so that it correctly realises there are no "extra colormaps" actually in SRB2's files, rather than telling you there are 6 extra colormaps on game startup (or however many WAD files total you have added).
For those who don't know what the function does, it searches for C_START/C_END markers, and if they exist, adds any lumps inbetween to a list of extra colormaps internally. They are never used by the game though, since we last supported colormaps of that kind so long ago I don't think anyone remembers when anymore (definitely more than a decade at least).
Merging to next since I don't know if this would cause any netplay issues or not tbh.
See merge request !182
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.
Jet Jaw crash fix
Turns out not having MF_SHOOTABLE can cause the Jet Jaw to endlessly loop between the two states, until somehow LUA_CallAction inexplicably causes Z_StrDup to crash anyway (that one's a mystery to me, I'm not going to look into it right now). I tweaked A_JetJawChomp so this endless loop can't happen anymore.
See merge request !176
* GE_NIGHTSPULL (for it to chase you once paralooped) - Sun emblem
* GE_NIGHTSITEM (for hidden until paralooped) - Moon emblem
Combined means that you essentially have to loop it twice.
Also, revamped NIGHTSITEM to suck a little less (and have more compatibility with MT_EMBLEM).
<Alam_Squeeze> p_floor.c:2932: warning: 'widthfactor' might be used uninitialized in this function
<Alam_Squeeze> p_floor.c:2932: warning: 'heightfactor' might be used uninitialized in this function
<Alam_Squeeze> m_menu.c:1907: error: initializer element is not constant
<Alam_Squeeze> m_menu.c:1907: error: (near initialization for `OP_ScreenshotOptionsDef.drawroutine')
<Alam_Squeeze> m_menu.c:9353: warning: 'M_DrawScreenshotMenu' defined but not used
<Alam_Squeeze> Makefile:770: recipe for target '../objs/Mingw/Debug/m_menu.o' failed
<Alam_Squeeze> make: *** [../objs/Mingw/Debug/m_menu.o] Error 1
* Search case is now handled via cvar instead of assumed based on system.
* filemenusearch (previously strsystemstr) uses static char[] to prevent stack suffering.
* New cvar for searching from start of string instead of anywhere in it!
* Menu tweaked for the above.
* Reverted slash from pathsep.
Level specials setup stuff
Some changes to level setup, largely inconsequential for gameplay but maybe helpful for Lua scripting:
* gravity, weather, and some other internal variables are set to their defaults before loading things, so their values from a previous level don't affect mobj spawning potentially
* Tag lists are also initialised before loading things, so that tag-based search functions (such as P_FindSpecialLineFromTag) can be used internally for the maces and particle generator. This should probably extend to Lua as well
* the level header "forcecharacter" no longer recognises "255" as "None" anymore. This is because it no longer takes skin numbers (as of whenever that change was added... version 2.0?), and level headers are auto-cleared when edited anyway.
See merge request !88
