Blender must have an active shape key before shape key animation will work.
This fixes the models being locked to the first frame until a shape key is
selected via the UI.
I /did/ see the warning about vertex index 0 in the obj importer script,
but I didn't take it seriously enough. This fixes both the twisted texture
on a couple of faces, and the truly mangled tris when exporting (using
invisibl.mdl for testing).
There seems to be some problems with the UVs, only one frame is exported,
and various model params don't get set (eye position, size, bounding
radius, synctype, flags), but the size and shape look right in qf :).
Except for the normal index in the frame bounds (and potentially frame
names with junk after the terminating nul), the output is identical to the
input for:
mdl=MDL().read("invisibl.mdl")
mdl.write("test.mdl")
