Stop tracking when battery level is low

[cbalster]

As someone suggested in a playstore review, the app probably should stop tracking when battery level is really low. This is probably best implemented by listening to BatteryManagers BATTERY_LOW and BATTERY_OKAY broadcasts to determine when the battery enters and exits the low state and stopping/restarting the gps and server updates accordingly. Also the notification should reflect this.

Questions: Should this behavior be an option? Should there be a way to force resuming tracking?