It now takes a context pointer (opaque data) that holds the buffers it
uses for the temporary strings. If the context pointer is null, a static
context is used (making those uses of va NOT thread-safe). Most calls to
va use the static context, but all such calls have been formatted
consistently so they are easy to find when it comes time to do a full
audit.
There are still many issues to sort out, but the basics are working.
Problems:
rendered fullbright (no lighting done)
normals are ignored
extra textures (glow etc) not used/loaded
4 models on the screen don't seem to be a problem.