City preferences in Settings.bundle, bug fixes

-Added the ability to turn automatic city detection on/off as well as a
manual city selection in Settings.app (focusing on North America and
major European cities for now), managed in-app with NSUserDefaults
—Note that all staging.citybik.es/* and api2.citybik.es/* APIs are down
at the moment, hopefully that will be fixed soon, but the cities that
use those URLs will not work…
-Fixed bug with incorrect bikingState being set when station data did
not load successfully
-Fixed map annotation view bug showing a green station when stationID
== 0 and sourceStation == nil