[Lowfer] Use of NMEA strings for GPS 1 pps time tagging

[Lyle Koehler]

I'm using a Motorola Oncore GPS board -- one of the boards that BGMicro was
selling for $15 a couple of years ago. It's sending the GPRMC, GPGSA, GPGGA
and GPGSV sentences, which look like they are having a hard time getting
squeezed into one second. So far AFRICAM (actually I'm using Bill's SETDOS
to set the DOS clock) always manages to catch and maintain the correct time.

Lyle, K0LR