For some reason, the X "expose" event handler was *directly* calling

the display handler in the client.  (Okay, it was calling a function
that operates on the window handle.)

If you have any complexity to the display code, this can be painful
to watch.  I can't think of a good reason to do the display immediately,
so I fixed the code to do a glutPostRedisplay().

git-svn-id: svn+ssh://svn.code.sf.net/p/freeglut/code/trunk/freeglut/freeglut@461 7f0cb862-5218-0410-a997-914c9d46530a