spearmint: Add support for FAKK's spriteScale and spriteGen shader keywords

I haven't figured out if I use axis the same as FAKK. I think it matches
the description in the FAKK shader manual and seems logical enough.
spearmint: Fix FAKK/Alice/EF2 default light grid size

FAKK/Alice use a different default light grid size than Q3.
Using correct size fixes reading the light grid data.

Lighting isn't the same as FAKK (blue lights in fakkhouse don't effect player).
Probably because new entlights and lightdefs lumps aren't supported yet?
Maybe lightgrid is only environment light (shadows, sky light).

EF2's qfiles.h uses the same default light grid size as FAKK.
EF2 maps have 0 length light grid lump, so it hasn't been tested.