[pbmserv] New improved Cubox

[Cameron Browne <cameronb@optusnet.com.au>]

The Cubox rules have been relaxed so that players can stack on *any* three 
touching pieces that form a flat triangle: 
http://www.gamerz.net/pbmserv/cubox.html

This should hopefully fix a problem with the previous rules resulting in 
too cold a game.

The rule change will apply immediately to all current games. Please 
challenge me to test it out:

  cubox challenge <yourname> camb

Cameron