User location detection improvements, no redundant local notifications

-startUpdatingCurrentLocation when app becomes active, when mapView
appears, and when preparing a new bike route
-update location button pans map to mapView.userLocation instead of
waiting for a new location from the locationManager
-no more updateLocationState (due to above change)
-calling updateDistancesFromUserLocation: from
sortLocationList:byMethod: was redundant; deleted
-Avoided doubly alerting the user with sound/vibration on a local
notification by only doing it manually if the app was active
-Log message added to application:didReceiveLocalNotification:
-comment cleanup