Battery burn rate

A simple data field to display the battery burn rate in percent per hour. I wrote this because I wanted to see the effect on my battery life of different sensors, or changing settings on the Edge device. With this you can tell write away how much battery life you're losing, from, say, turning up that screen brightness.

Cap the maximum displayed battery lifetime to prevent unuseful values from appearing while the data stabilizes. Support newer Edge devices (x50 series) potential bug fix to prevent displaying nonsense time remaining calculation