Comment 78 for bug 359392

Slightly improved version of rotate-forever, thanks Ronald for the original version! This one

  - Uses positive arithmetic, since % doesn't turn negative numbers into positive numbers and thus rotation wouldn't work at all for me (It tried to scroll to -1280).
  - add date output every two seconds to the screen (to see when it started freezeing); note that if you are unlucky, it freezes at the wrong desktop and you can't see it
  - add date output to ~/rotate-forever.log, so that after a reboot you can check whether it was the screen freezing, or X.org crashing completely