Fix iOS 5.1 localStorage problems

[toddanglin]

With the introduction of iOS 5.1, localStorage and WebSQL are treated as temporary data stores (deleted when the app is closed). TeamThing depends on these APIs to remember user credentials and settings, creating a bad repeat user experience in iOS 5.1.

We need to research and implement a workaround for iOS 5.1 so repeat users do not have to regularly re-enter credentials and choose their team.