#7 Garnet windows close ungracefully

[Robert P. Goldman]

At least on Allegro CL 7.0 on Linux, if you close a
Garnet window using the X window manager close option,
Garnet gets into an error, attempting to write to a
destroyed window.

I suspect that this just means that we need to
reexamine how (if?) Garnet traps X window close events,
and tidy things up there.