#11 Convert GPS positions to WGS84 for display or transmit

[Curt Mills]

Convert non-WGS84 GPS input to WGS84 positions before
displaying, storing in the database, or transmitting
them. The APRS spec calls for all positions to be in
WGS84. Note that Garmin GPS's and perhaps others
change the datum in the NMEA data per user settings. A
special NMEA sentence specifies which datum is being
used for Garmins.