- fix incorrectly shown awake, sleeping, charging and discharging,
- remove unneeded debug mode and logging to external file,
- prevent showing values like inf, -inf, nan in estimated times
(we now show "n/a"), and values below zero,
- show extra confirm box when we want to reset data,
- show time in format xxhxxm instead of only pure minutes,
- check at initialization that the device was charging when it was
turned off (battery level larger than at the time of exit).
1. Android.getScreenBrightness() is used in frontend/device/android/powerd.lua to retrieve the frontlight intensity.
2. kosync.koplugin won't save settings for whisper sync.
3. batterstat.koplugin won't work correctly if several on* events are fired.
