Certain views are unresponsive to updates

The people and photo gallery views are unresponsive to invites sent from other users unless you restart the application (or somehow force the underlying observable objects to trigger a view to update). There seems to be problems where the ObservableObjects used in the views do not cause UI updates.

Additionally on iPad devices, after accepting/rejecting all invitations on an invitation view, we are left on an empty details view screen (iOS correctly goes back to the master view). I'll if its possible/easy to implement programmatic navigation to the previous view.

I'll also investigate/attempt to remove the view update hacks and fix the relevant ObservableObjects to ensure views are updated when the relevant published properties change.