Remove really old crap

- special case for Apollo Domain/OS: that stuff is so old it's already
  on Bitsavers. Other OSes like Ultrix and 4.3BSD should follow...

- defines for Ultrix, Convex, SVR3, SVR4, PCS (Cadmus Munix): dead
  as a doorknob

- curses, termcap defines: those were used only by the client, which
  hasn't existed in Unreal's tree for decades

- valloc went away with kaniini's dbuf rewrite
Remove tokens and server numerics from protocol docs