Description of Problem:

   If the METAR weather data (which I presume 
   gweather uses) contains the phrase "CAVOK"
   (this replaces cloud and visibility data) 
   gweather doesnt know what to do. However,
   CAVOK means "Ceiling above 5000ft and 
   visibility greater than 10 kilometers."

   Thus a "sunshine" icon would be the one 
   to use here, since very often CAVOK means 
   sunshine - although it can be also overcast
   at 5000 feet by the definition - but in reality
   this happens rarely.

So, it would be nice if, in case of CAVOK,
gweather would use "sunny" icon and set
Visibility: to "over 10 km" or whatever that is in
miles if the user wants miles.