chore: Use $II as a talker ID to extend compatibility with other software

[cmotelet]

To extend compatibility with other software (e.g. SailGrib WR) the talker ID is set to $II.
Very proprietary sentences remain with their original talker ID ($PNKEP, $PSILCD1, $PSILTBS)

[tkurki]

Are you positive that II and not GP is the correct choice for also GGA and APB? II is Integrated Instrumentation and GP GPS per http://www.catb.org/gpsd/NMEA.html#_talker_ids.

[cmotelet]

I chose $II because I think it is the most common talker ID for all sentences.
Since Signal K is not a GPS and is really the one who builds the sentence, I think it is appropriate for most standard sentences except those that are proprietary.
The original choice to use $SK was the right one, but since it is not necessarily official and as we have seen, some applications may refuse it.

[tkurki]

Published as @signalk/[email protected] - thank you!