Add sentences: HDG, HDM, MTW, ROT, TXT, PHTRO, PRDID, PSONCMS. + more

[aldas]

• Add sentences: HDG, HDM, MTW, ROT, TXT, PHTRO, PRDID, PSONCMS (last three are proprietary sentences)
• Improved docs with formats and examples and links.
• Add NMEA 2.3/4.0 related field (FAA mode and Navigation status)
• GLL - added FAA mode field (NMEA 2.3+)
• GNS added Navigation status field (NMEA 4.1+)
• GSA added System ID field (NMEA 4.1+)
• GSV added System ID field (NMEA 4.1+)
• RMC added FAA Mode (NMEA 2.3+) and Navigaton status (NMEA 4.1+) fields
• VTG - added FAA mode field (NMEA 2.3+)
• Added Makefile to make testing/checking easier from command line

Note: I think MTK implementation is not correct. MTK is command protocol embedded into NMEA sentence. Fields that current MTK struct has are meant for MTK packet "PMTK001" but actually MTK packet can have variable amound of data fields.

See:

• https://www.rhydolabz.com/documents/25/PMTK_A11.pdf
• https://www.sparkfun.com/datasheets/GPS/Modules/PMTK_Protocol.pdf

Note 2: I think p.EnumString(4, "variation direction", East, West), implementation maybe needs counterpart that sets error when value is empty "" currently it does not error. Sometimes is OK when field is empty but times it is not.

Note 3: in newer sentences testcase tables are inside test methods. This is because in that way Goland allows you to execute each testcase separately if you want - which is handy. VsCode does not have that feature yet but there are open feature tickets so it will probably land in there also.

[icholy]

This is great!

[icholy]

@adrianmo this LGTM, but I won't merge until you've had a chance to look it over.

[adrianmo]

This is fantastic - what a contribution!

Thanks for the Christmas present @aldas 😄