Let each screen get width and height in as a parameter on draw() instead of hardcodin...

[ccbs] / bigscreen / tinyptc / AUTHORS

X11 version done by Alessandro Gatti <a.gatti@tiscali.it>
XVideo/XSHM target written by Fred Howell <foohoo@shaw.ca>
Original windows version done by Glenn Fiedler <gaffer@gaffer.org>