Include the Jquery countdown library v2.0.3

Sources: http://hilios.github.io/jQuery.countdown/
Include a countdown in the meeting view

Based on the work from Mohan (mpduty)

Fixes https://fedorahosted.org/fedocal/ticket/121
Update the update_date_rec_meeting method to take a given date_limit

This date_limit allows retrieving the last or next meeting in the recurence
compare to the date_limit provided.
Retrieve the next occurrence of the meeting compared to from_date when viewing a meeting
Use the next occurrence of the meeting in the countdown
Enable editing a meeting at the exact date asked
Fix getting the date_limit

When want the date_limit to be the start of the week since we want the
next meeting from that date.
Import the jquery-ui as well otherwise we cannot open, close and open again a pop-up dialog
Create the Date.UTC outside of the countdown function, makes debugging easier
Fix displaying the countdown in full view mode
Change from id to div to fix displaying the countdown when re-opening the pop-up window
Explicitly include the js in the body or the jscript block according to if the template is view full or not
No need to re-import jquery itself
Import jquery everytime is not the best solution but remains the only way to not have errors atm
Add the meeting_id in the class name so that meetings do not conflict
Properly integrate the countdown script

- Use an identifier instead of a class, as it should be
- Do not duplicate jquery imports, as it should be
- Use $this instead of parsing the DOM again, as it should be
Fix displaying the dialog multiple time by not caching is and resetting it on close
Merge pull request #125 from fedora-infra/countdown

Countdown