GUI bug in advances

[Steven S. Dick]

There is a bug that causes the display to be drawn wrong for
cities near the edge of the map.  I'm not sure if the bug is in
the GUI itself, or in the advances game.

I reported this about a year ago, but with a different game.
Unfortunately I don't remember what the fix was.

This can be reproduced with 

xconq -g advances -M 10 &

and then build a city on the edge of the map.

If anyone is having trouble reproducing this, I have a 25k png file that
clearly shows the problem...

	Steve