Fix assignment with AG_Window* cast.


git-svn-id: http://odamex.net/svn/root/trunk@3691 b0bcef46-2027-0410-bd56-ab726e9a1d04
-Retry the PortMidi volume slider repsonse changes in 3690. Hopefully this should not decrease the music volume when the slider is adjusted.

git-svn-id: http://odamex.net/svn/root/trunk@3692 b0bcef46-2027-0410-bd56-ab726e9a1d04