Defer submit until connected

[micheledallatorre]

Add functionality to defer submission of the form until connection is re-established.

If the user is not online, the app should notify the user that they are not connected, and save the users' data to submit automatically when re-connected. In this case, the review should be deferred and sent to the server when connection is re-established (but the review should still be visible locally even before it gets to the server.)