[racket] Three new builds

Three new builds are now available as nightly builds (and will be
included in the next release):

* Two x86_64 debian builds, thanks to Mason Loring Bliss for
  volunteering servers for doing this.

* A Windows x86_64 build.  Note that there's enough tricky details
  there that it's likely to still have problems.  If you use such a
  machine it would be nice to try it out.

-- 
          ((lambda (x) (x x)) (lambda (x) (x x)))          Eli Barzilay:
                    http://barzilay.org/                   Maze is Life!