make a test program for correctness of opening rack scores
-- meh, i have tested it. going to put off 
make a test program for speed of opening racks
-- putting this off as well, the really interesting thing
   will be overall speed
filldawg!
-- filldawg works!
nonempty board move finding
-- starting on this
   write these:
   (place-move board move)
   (update-crosses board &optional last-move)