- merge net_udp6.c into net_udp.c
- kill off ctf/q_shared.c, it's identical to src/q_shared.c
- clean up the #ifdefs that are throughout the code to be has-a
  tests instead of is-a. (using HAVE_* from configure instead of __blerg__)
- separate the video refreshers
- check that the parts install into the right places
- use DATADIR to find game data, rather than in same directory as libraries
  this way, it can follow FHS: libs in /usr/lib/games/quake2 and data in 
  /usr/share/games/quake2, for example
- the video refresher loader code in src/vid_menu.c needs cleaning up, it's
  utter bollocks at the moment.  all the structs are very fragile, depending
  on specific ordering of each element.
- fix va_list as per  http://gozer.quakeforge.net/list-archives/quakeforge-cvs/2002-April/000151.html, http://www.quakeforge.net/cgi-bin/viewcvs.cgi/quakeforge/libs/util/dstring.c.diff?r1=1.8&r2=1.9