Merge branch 'next' of https://git.do.srb2.org/STJr/SRB2 into model-features

src/r_plane.c

src/r_skins.c

src/r_splats.c

src/r_textures.c

src/r_textures.h

src/sdl/Srb2SDL-vc10.vcxproj

src/sdl/Srb2SDL-vc10.vcxproj.filters

src/sdl/mixer_sound.c

vcpkg.json