Messed with GL loader some more.

I've branched well off of upstream glloadgen since they don't appear to be very active in between GL versions.

1) Changed how the address finder functions are set to be more sane.
2) Added *all* possible extensions. For the lulz.
3) Fixed a retarded bug in IsVersionGEQ.
4) Slapped myself for not seeing IsVersionGEQ bug earlier. Most important change.
Fixed gl-subsystem.c to reflect changes to GL loader API.