Distance from user location added to stations/addresses

-All MyLocation objects now have a distanceFromUser property, updated
with CLLocationManager
-Selecting a destination from the tableView opens a UIActionSheet which
will prompt the user to begin navigating to that destination
-"Navigate" feature (aka startBiking: method) started (switch to map
tab, refresh bike station data, sort by distance… eventually select the
closest to you and N (default=3 for now) closest to your destination,
show that in the map, start the timer and start tracking the "goal"
station
-geocoder now uses current user location for hint region
-distanceFromUser properties for all objects in the
LocationDataController are updated every time we get a new user location
-deleted segues to detail view controllers, preferring action sheets
instead for now