User sometimes stuck in checking-in-dialog when request stalls

With no cancel button, if the check-in request stalls, sometimes users get stuck on check-in dialog screen with nothing but a throbber and the "Checking in..." message.
The app then needs to be restarted, as there is no other way out of the function.

We should show a button to return to the main screen after some time (10-15 seconds) or otherwise mitigate this problem.
