Add support for SeaTalk protocol #67
Description
Add support for Raymarine SeaTalk protocol by adding a layer of listeners and message parsers on top of raw $STALK sentence parser.
http://www.thomasknauf.de/seatalk.htm
http://www.gadgetpool.de/nuke/images/articles/bridge128sd/ManualBridge128SDV3.01.pdf
$STALK,cc,p1,p2..,pn*xx
- cc = SeaTalk Command
- p1, p2 .. pn = Parameters
- *xx = NMEA checksum
Somewhat real examples provided here:
$STALK,30,00,0C - Switch ON illumination on SeaTalk instruments.
$STALK,30,00,00 - Switch OFF illumination on SeaTalk instruments.
Talker/sentence id is unusual but ST and ALK don't seem to overlap anything "standard", so it's probably quite safe to have fake ids in TalkerId and SentenceId enums.