Battery: pick up changes in the settings

Previously the settings were only updated on powerup, this
adds an updated flag to avoid making a static variable for
all the settings.
FlightBatteryState: default to one second updates

50000 is just silly and the object is only initialized
when it is being used anyway.
Shared flightbatterysettings:Renamed SensorCalibrations and created new field

SensorCalibrations was renamed to SensorCalibrationFactor
Created SensorCalibrationOffSet field. A new field was created because
it uses different units than SensorCalibrationFactor.
Battery Module:Use offset fields and scale factor to use mU.

The factor units were recently changed to use mV/V and mV/A but they
weren't properly scaled on the module.
UAVOMavlinkBridge:Use renamed SensorCalibration fields.
GCS Battery:Implement offset fields, allow higher than "1" val on factor fields.
Merge pull request #1038 from peabody124/battery_settings_change

Battery: pick up changes in the settings