GetOnBattery() -> :on-battery (bool)
GetLowBattery() -> :on-low-battery (bool)
CanSuspend() -> :can-suspend (bool)
CanHibernate() -> :can-hibernate (bool)
also add a new property for the daemon version
:daemon-version (string)
introduce a new Changed() signal that replaces
::LowBatteryChanged()
::OnBatteryChanged()
Also fix a few bugs
- we need to compute ::on-battery and ::on-low-battery *after*
the actual device is updated
- need to fire Device::Changed() before Power::DeviceChanged()
otherwise devkit-power --monitor-detail lies
also fix up libdevkit-power and devkit-power(1) to use these changes.
