- add some basic bmpman functionality to grstub, since it needs to do something at least
- add missing gr_* function ptrs to grstrub
- (re-)enable radar and hud setup functions that used to crash (problems are fixed now)
- deal with default pilot file properly (also caused a bmpman headache)
- don't bother with Multi_common_icons[] in standalone mode (they don't load, so don't let them unload either)
move color and shader functions to 2d.cpp since they are exactly the same everywhere
don't bother with the function pointer for gr_set_font(), it's the same everywhere anyway