Changes for iOS 6 Updates

I've updated the code to work with the latest SBJson library and added back the code that shows the OBASituationView and OBASituationsView since these two are needed to show service alerts. It appears that the situation views were removed with commit 58ddff9 for some reason.

These two changes were made to support changes to the OneBusAway app that will add iOS 6 support.