Automatic city detection

-Uses api.citybik.es/networks.json to determine the city the user is
closest to and automatically downloads that city’s bike data.
-Saves current city URL to NSUserDefaults and recalls it on application
launch
-Bug fix to use most up-to-date user location when Loc button is pressed
-Only deletes station ID number from station name when using Capital
Bikeshare. Need to make it more of an automatic detection if a station
ID is prefixed onto any given station name.