Expose more music-related functions to Lua

See merge request STJr/SRB2!817

NiGHTS Mode menu fixes

See merge request STJr/SRB2!841

Fix division-by-0 crash from 100% gamepad deadzones, and lack of input from 0% deadzones

See merge request STJr/SRB2!838

Fix incorrect newdisplayplayer in forced ViewpointSwitch

See merge request STJr/SRB2!814

Actually use the "SCREENSHOT OPTIONS" header for its menu.

See merge request STJr/SRB2!832

Increase the length of the player input buffer

See merge request STJr/SRB2!835

Fix buffer overrun with players with no associated node

See merge request STJr/SRB2!810

Skins refactor

See merge request STJr/SRB2!843

Fix NiGHTS Attack crash after render mode change

See merge request STJr/SRB2!837

Fix HWR_DrawFlippedColumnInCache ignoring chroma key TF

See merge request STJr/SRB2!826

Replace NextTexAvail with glGenTextures

See merge request STJr/SRB2!828

Fix ASTBlendPixel blending with nothing

See merge request STJr/SRB2!827

Archive sprite2 Hotfix

See merge request STJr/SRB2!845

Fix desyncs never recovering if node and player mismatch

See merge request STJr/SRB2!842

One line fix: don't assume 0 (aka SPR2_STND) is the default value for sprite2, but rather what the state sets for it

This fixes some issues with a custom character tested during netplay, which did not have SPR2_WAIT sprites and therefore fell back to SPR2_STND sprites. Unfortunately, the fact they used SPR2_STND instead meant the sprite2 was not synced at all!

(oddly enough, this actually revealed some secret file dependencies previously included via r_things.h! I also needed to include d_player.h in r_skins.h itself it seems)

Set the "spritename" variable within R_AddSingleSpriteDef rather than externally to it, since R_InstallSpriteLump is the only place it gets used anyway

This way we don't have to make it some extern in order for r_skins.c to use it

Fix Special Stages crashing upon taking damage

See merge request STJr/SRB2!839