Allow specifying geometry on command-line

Requested by Paul Bodenstab (~bobo666):

I like GEDA tools in general and GSCHEM in particular, however, one annoying problem is that I cannot invoke it on a command line and specify the window geometry and placement that I would like. It would be fantastic if I could invoke GSCHEM with the following
command line. So many other linux tools support these command line switches:

> gschem -geometry 700x600+0+0

A feature like this is especially useful when a multiple monitor setup is used. One monitor can be devoted to Gschem and the other
monitor can be devoted to various terminal windows.

I hope this suggestion will be useful for others as well.

Thank you.