Date format configuration

The goal of this PR is to make possible to have a different date format than the default mm/dd/yyyy and the 12 hours clock.

By default it keeps the american dates but you can decide to use a different "locale" file.

The solution might not be the most elegant and there is some redundancy as the date format for the backend and the frontend is different.

Many javascript libs have been updated in the process, mainly because documentation can be found more easily. I also removed query-ui as it seemed to have been used only for the datepicker.formatDate which I replaced with the bootstrap-datepicker already used.

Would love to hear your thoughts!
I think the approach here is fine, but can you untangle the statement a bit so it's easier to read?