Version 8: GTK+2.0 port?
    I looked into this but does not seem a way to build for
      Windows, Cygwin, and Linux reliably.

other stuff to do
    1. The calculator portion does not work for big numbers, i.e. where
      one can type in math operations and see the abacus perform.
    2. When displayBase != base calculate with strings instead of
      "long long".  I.e. the number of rails can be large if displayBase =
      base, but may error out when this is not true for a large number of
      rails.
    3. Also allow for locale to allow "," for "." and vice versa.
    4. Redesign the bead so that it gets kicked over across rail or slot,
      so that the gap between the beads is not necessary.
