the BatteryStats base class shall be able to tell the total battery pack
voltage. for that reason, and to avoid code duplication, the voltage is
now handled in the base class and treated as a datum that is common to
all battery providers.
* adding data age to battery data
* Add battery enabled flag
* Webapi and websocket api for Battery
* Webinterface for battery
* fixed bug due to naming inconsistencies
* cleaned up rounding
* dist update
* change typename to uppercase
* reverting to original file