[frontend] put all controllers.js to 80 cols.
[frontend] approaching quiz answers storage.

Now has a scope object named quiz_answers that store answers like:

  {
    "<question_id>": <answer_id> / "free answer string",
    ...
    ...
  }

That's not ready because for free answer questions, i do not know yet the answer
ID that is used to match the free answer entered by a participant...