Committed change from Nigel to fix the joystick bug. (The joystick

Committed change from Nigel to fix the joystick bug.  (The joystick
code was not setting the GLUT window prior to calling callbacks.)

Please verify.  If so, this closes out, I think, the latter half of
that bug report, so anyone with the means to modify/close bug reports
should do so upon verification of the fix.

git-svn-id: svn+ssh://svn.code.sf.net/p/freeglut/code/trunk/freeglut/freeglut@242 7f0cb862-5218-0410-a997-914c9d46530a