PGNs 127501,127606,127508: Battery Power

[tkurki]

Add support for

127501: Binary Switch Bank Status"
{"timestamp":"2015-01-15-16:25:06.017","prio":"3","src":"209","dst":"255","pgn":"127501","description":"Binary Switch Bank Status","fields":{"Indicator Bank Instance":"0","Indicator":"Off","Indicator 2":"Off","Indicator 3":"Off","Indicator 4":"Off","Indicator 5":"Off","Indicator 6":"Off"}}

127506: DC Detailed Status
{"timestamp":"2015-01-15-16:25:15.899","prio":"6","src":"177","dst":"255","pgn":"127506","description":"DC Detailed Status","fields":{"SID":"89","DC Instance":"1","DC Type":"0","State of Charge":"72","Time Remaining":"40350","Ripple Voltage":"0.10"}}

127508: Battery Status
{"timestamp":"2015-01-15-16:25:15.901","prio":"6","src":"177","dst":"255","pgn":"127508","description":"Battery Status","fields":{"Battery Instance":"1","Voltage":"12.83","Current":"-0.8","Temperature":"8.65","SID":"89"}}

[tkurki]

127508 done in #25

[sbender9]

127506 done also.

[timmathews]

127501 pending resolution to SignalK/specification#187, SignalK/specification#241, and/or SignalK/specification#441.