Need Confirmation Numbers for Each Transaction

[DerekEdwards]

In general it seems that it would be useful for actions to return some sort of confirmation number that one-click can retain and possibly present to the user. For the create_trip method, that would be the trip_id. For cancel_trip, it could be useful to return something as well. RidePilot doesn't presently create anything for that, of course, but that could be something down the road.