TODO

   1 Debug exam mode (and open too...): Vue.js warning + shift questions (not showing solution)
   2
   3 Replace underscore by lodash (or better: ES6)
   4 Replace socket.io by Websockets ( https://www.npmjs.com/package/websocket )
   5
   6 time per question (in mode "one question at a time" from server...)
   7 compute grades after exam (in teacher's view)
   8 factorize redundant code in course.js, monitor.js and (TOWRITE) grade.js
   9   (showing students list + grades or papers)
  10 monitoring: main teacher should not be asked for pwd, and button "send feedback" hidden for others
  11
  12 -----
  13
  14 TODO: format général TXT: (compilé en JSON)
  15
  16 10 (time)
  17 1 (fixed)
  18 Introduction (multiline, from third line ; \n --> <br>)
  19
  20 [Intro q1, multiline]
  21
  22 q1 txt
  23
  24 answer q1 (multiline txt)
  25
  26 q2 intro (multiline)
  27
  28   q2.1 [intro optional]
  29
  30     q2.1 txt
  31
  32     q2.1 options:
  33     + good
  34     - bad
  35     - bad ...etc
  36
  37     answer (integer array, one line)
  38
  39   q2.2 [intro optional]
  40
  41     q2.2 txt
  42
  43     answer (html multiline)
  44
  45 Conclusion (last block)
  46
  47 =====
  48
  49 Seems that GUI would be easier, then summary in YAML file + parse from YAML