Add "GN" NMEA TalkerID support for GPS driver #125
Description
In gps/NmeaParser.java, line 48-51, for the message type identifier, some devices use "GN" instead of "GP" as TalkerID, it's better to support that as well. In that case, identifiers will look like
// NMEA Message Types
private static final String GGA = "GNGGA";
private static final String GSV = "GNGSV";
private static final String GLL = "GNPGLL";
private static final String RMC = "GNRMC";