Bug 9905 - Use DataTables on calendar page

Bug 9905 - Use DataTables on calendar page

The calendar management page uses the old tablesorter plugin. This patch
replaces tablesorter code with DataTables.

In order to easily sort date columns under various dateformat system
preference settings, date columns now sort based on an unformatted date
in a <span>'s title attribute (requiring the patch for Bug 9887).

To test, view the calendar page--preferably with plenty of existing
holiday data to populate the holiday summary tables. Confirm that
sorting works correctly on all sorted tables with the dateformat
preference set in all settings.

Signed-off-by: Chris Cormack <chris@bigballofwax.co.nz>
Signed-off-by: Katrin Fischer <Katrin.Fischer.83@web.de>
Note: This has to be tested together with the patch for bug 9887.
All tests and QA script pass.
Signed-off-by: Jared Camins-Esakov <jcamins@cpbibliography.com>