[sugar] Suspend in build513.

[Chris Ball]

Hi,

In build513, the power button is hooked up to performing suspend to RAM,
but with the display left on:

* It's normal that the cursor will freeze when you hit the power button.
* Any "button" (power button, game keys) will wake the machine back up;
  in the near future the touchpad and keyboard will wake back up too.
* If you have a B2 machine, the display image will not be stable during
  suspend unless a hardware modification is present -- the screen will
  fade to white over time.  Suspend should still work.
* Without a hardware modification to some early machines, the keyboard
  and touchpad may not come back after resume.
* Wireless should come back (and still be connected) after resume.

On any B3 or B4 machine, everything above should be working.

Since we're now using the power key to suspend, rather than to shutdown,
the shutdown button has been replaced with a mouseover icon over the
"XO" character on the home screen.

In future builds, the power button may turn off the screen immediately
as well as suspending, with suspend-with-screen-on reserved for when we
automatically trigger suspend due to a period of idleness -- we don't
want the idleness suspend to be noticeable.

Thanks,

- Chris.
-- 
Chris Ball   <cjb at laptop.org>