Send setup survey responses to the server

The setup survey presentation & submission logic had gotten disconnected. This hooks them up again so that setup survey responses are actually sent to the server.

Incidentally, as part of that:
* Now setting participant IDs
* Discovered that CHECKBOX questions were missing a name value; added that.
Hmm, why not set it to null? That way you can simpl do ```if (participantId) return;```  at line 63 below. It'll also manifest bugs if you are trying to access it before generating an actual value.