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.
nit: You could make this idempotent, such as ```function generateParticipantId```.

Then at line 85 you'd just say 
```javascript
chrome.storage.local.get(cesp.PARTICIPANT_ID_LOOKUP, function(lookup) {
  var participantId = (lookup && lookup[cesp.PARTICIPANT_ID_LOOKUP]) ?
      lookup[cesp.PARTICIPANT_ID_LOOKUP] :
      generateParticipantId();
  cesp.participantId = participantId;
}
```
I feel this is a bit cleaner, but up to you.