The Windows build of MGED does not currently have a functioning
display manager so raytracing directly into the Graphics Window is not
possible.  To raytrace, users should either render directly to a
window by utilizing the 'rt' command, or by launching a framebuffer
server via 'fbserv' on the command-line.  The framebuffer can be "set
default" by adding a -F# (e.g. -F0) to the "Other Options" field of
the "Advanced Settings..." panel of the Raytrace Control Panel,
selected via File->Raytrace.
