This is intended to make it easy to have a glimpse at the content of
an event, when its width is not sufficient for its content to be
displayed (without overflowing its parent).
It uses an external jQuery library to display tooltips: named _tipso_
(https://github.com/object505/tipso).
This is the first step to include a visual calendar to Poulpe,
only including a "day view" as of now (i.e. events hour-by-hour from one date to another).
More views may be added at a later time.
It is **NOT WORKING YET**!
The CSS has been broken on this branch, and will have to be fixed before the calendar can work:
* the CSS of the calendar needs to be adapted to the environment and design of Poulpe;
* add actual links to enroll/un-enroll to an activity (cf. `Event` class in `calendar.js`);
* other small tweaks :)?
Finally, this view is likely to require the addition of start and end date change,
so that an user can browse events over several days (cf. `setStartDate` and `setEndDate` methods of `Calendar` class in `calendar.js`).
Note that this code should be better re-written (e.g. in Typescript, split between files, using more/better design patterns) at a later time.
It should nonetheless be easy to fix it and use it right now (see above requirements for this).
