[Xastir] USNG Support

[Brett Friermood]

To what extent does Xastir support USNG coordinates? I am investigating a
relatively simple use case of marking a location on the map using a
object when given coordinates in USNG format.

I recall seeing something more in depth before, however I'm currently
unable to find any mention of it on the internet, in the list archives, or
even in the little bit I've browsed the code. The only thing I am able to
find is a couple mentions of it being supported, however no additional
information.

I have a work around by using an external converter and inputting via UTM
or Lat/Long, just curious if I am able to directly input via USNG.

Thanks,

Brett KQ9N