Corrected a bug w.r.t. display and joystick events. When getting ready

Corrected a bug w.r.t. display and joystick events.  When getting ready
to sleep, we need to go through ALL windows to check for pending joysticks
and to check for pending redisplays.  I was just going through all TOP-
LEVEL windows.  Eeek.  This won't do.

git-svn-id: svn+ssh://svn.code.sf.net/p/freeglut/code/trunk/freeglut/freeglut@205 7f0cb862-5218-0410-a997-914c9d46530a