Intermediate class for all NMEA data types.
Contains functionality to find particular NMEA strings, correct
string. Then extracts desired section of that string
searching multiple NMEA inputs if necessary to locate the
AUTO_UPDATE_SUCCESS, AUTO_UPDATE_FAIL or AUTO_UPDATE_CANT
public int updateNMEAData()
Tries to find the appropriate NMEA string by searching
multiple data blocks if necessary. IF the previous call was
Successful, then it will just go straight to that same data
block, otherwise, it will search all available datablocks.
Used when NMEA data is being updated in response to the arrival of
a new NMEA string (i.e. on forms which save all NMEA data from a
single string). An actual string is passed in, but there is just
a chance that it will be the wrong type in which case the default