Replace underscore by lodash (or better: ES6)
Replace socket.io by Websockets ( https://www.npmjs.com/package/websocket )

time per question (in mode "one question at a time" from server...)
compute grades after exam (in teacher's view)
factorize redundant code in course.js, monitor.js and (TOWRITE) grade.js
  (showing students list + grades or papers)
monitoring: main teacher should not be asked for pwd, and button "send feedback" hidden for others
(or just disabled)

-----

Draft format (compiled to json)

> Some global (HTML) intro

<some html question (or/+ exercise intro)>

	<some html subQuestion>
	* some answer [trigger input/index in answers]

	<another subquestion>

		<sub-subQuestion>
		+ choix1
		- choix 2
		+ choix 3
		- choix4

		<another sub sub>
		* answer 2 (which can
		be on
		several lines)

<Some second question>
* With answer

=====

questions group by index prefix 1.2.3 1.1 ...etc --> '1'

NOTE: questions can contain parameterized exercises (how ?
--> describe variables (syntax ?)
--> write javascript script (OK, users trusted ? ==> safe mode possible if public website)
Imaginary example: (using math.js)
	<params> (avant l'exo)
	x: math.random()
	y: math.random()
	M: math.matrix([[7, x], [y, -3]]);
	res: math.det(M)
	</params>
	<div>Calculer le déterminant de 
	$$\begin{matrix}7 & x\\y & -3\end{matrix}$$</div>
	* ...