rbn, ve7cc improvements and fixes

1. Add show/rbn command that allows one to see who is online and configured
   for RBN. See help sh/rbn for details.
2. Fixed issue with set/ve7cc mode adding unwanted newlines to output.
3. Attempted to make the QRG normalisation more "intelligent". This would be
   sooooooooo much easier if skimmers were calibrated more accurately.
4. Added CTY-3012 prefixes.