ACZ3 softlock fix

See merge request !1015

Don't repeatedly look for model texture files

See merge request !1009

Fix the Eggman signpost's background color

See merge request !1007

Faster and more correct OGL transparent surface sorting

See merge request !1005

GME cleanup and fixes

See merge request !1001

Fix missing bruh string in Lua side string options.

See merge request !1017

Backwards compatibility for shaderless hardware

See merge request !1003

MARATHON RUN

See merge request STJr/SRB2!941

OpenGL shaders

See merge request !724

# Conflicts:
#	src/hardware/r_opengl/r_opengl.c

Reduce calls to gme_set_equalizer in I_LoadSong by moving it to I_PlaySong
Return false if it fails to decompress VGZ data in some form.

Add dofile() to Lua

See merge request STJr/SRB2!969

Custom skincolor bugfixes

See merge request !971

Improvements to the in-game file downloader

See merge request !976

# Conflicts:
#   src/d_clisrv.c

Add a Snake minigame to the file transfer screen

See merge request !903

OpenGL draw call batching

See merge request !986

Shaders next merge

See merge request STJr/SRB2!985

Strike null-pointer-arithmetic error in BUFFER_OFFSET

See merge request STJr/SRB2!989

Fix OPENMPT deprecation error, openmpt_module_ctl_set

See merge request STJr/SRB2!990

Fix desynch when a player spawns

See merge request STJr/SRB2!977

Dashmode fixes

See merge request STJr/SRB2!909

Fix mouse being grabbed in continue screen

See merge request STJr/SRB2!983