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.
I'd consider making this required, and set a validator.

```ndb.StringProperty(indexed=True, required=True, validator=ParticipantIdValidator)``` 

You'll then want to validate that the id is actually 100 alphanumeric characters. You certainly wouldn't want <, > in it.