This patch adds a new CLI app called aprsd-dev. arpsd-dev is
used specifically for developing plugins. It allows you to run a
plugin directly without the need to run aprsd server.
This patch also adds the Weather Metar plugin called WxPlugin.
You can use it to fetch METAR from the nearest station for a callsign
or from a known METAR station id. Call WxPlugin with a message of
'wx' for closest metar station or 'wx KAUN' for metar at KAUN wx station
