[aprssig] Hiding APRSWorld maps in find.cgi

[Steve Dimse]

I added a new parameter, noaprsworld, which removes the APRSWorld map from the
page, allowing any of the others to be at the top of the page, which enhances
the display of the other maps:

http://www.findu.com/cgi-bin/find.cgi?call=K4HG-8&noaprsworld=1&radar=***

http://www.findu.com/cgi-bin/find.cgi?call=K4HG-8&noaprsworld=1&terra=4

http://www.findu.com/cgi-bin/find.cgi?call=K4HG-8&noaprsworld=1&topo=8

Steve K4HG