- for Quake-likes, WADs will be added as file system archives directly when the first brush is encountered since the wad key is ready to go by that point.
- after loading the .map and before constructing the BSP, what I call secondary textures (animation frames for Quake-likes) are added to the list, and the BSP's miptex data is filled.
- BSP miptex data is now opaque to the BSP process; the BSP simply copies the raw miptex information from the input. This simplifies the BSP structures and reading/writing routines.
- the img subsystem supports reading from raw miptexes now, although in practice this only happens for Quake-likes atm
- instead of a "wal cache", maps now have a "meta cache" which stores the metadata information for all games instead of just Quake II
- texture meta can now be ref'd out rather than needing to be copied every time (mainly only a gain for the std::string)
- wad.cc/wad.hh is gone; wads are now pushed into the filesystem archive
- fixed broken wad_archive
- fs subsystem iterated on a little bit; supports marking archives as external (only used for wads currently; see `LoadTextureData`)
- load_tga has better error handling
- add in foot-gun protection to the BSP readers; now they assert on failure to read instead of silently propagating that error throughout the rest of the process
- bsputil uses img stuff now, so it should handle palettes better