This is polyworld rev19.  It is the first official release version.

This version:
* combines the normal rev18, the optimal foraging code of rev18.of1,
  the changes needed for running on Apple campus machines, the changes
  needed for running under Irix 4.0.1, and the Apple copyright notices
* has new makefile.c and makefile.h to permit easy specification of
  Irix 3.2 or Irix 4.0.1 (and the AT&T versus SGI c++ compilers that
  go with them, respectively)
* has some of the new "smite" code, but is not fully implemented yet
* note that the optimal foraging code is still a compile-time option
  (#define OF1)
