Created GPSManager class.
Fixed Invalidation of too old locations.
Fixed threading error.
Added callbacks to GPSManager that notify about disabling and enabling of the GPS provider.
Added Javadoc for GPSManager class.
Removed OnLocationLost() for GPSManager and replaced it with the GPSManager status "NO_FIX".
Updated Javadoc for GPSManager.
Integrated GPSManager class in MapActivity.
Merge branch 'feature/gpsmanager' into develop