Bug 24093: Sorting indicators broken on list contents view

Bug 24093: Sorting indicators broken on list contents view

This patch updates the table markup for the lists contents view so that
the table sort state is correctly indicated by arrows in the table
headers. The markup changes allow the standard DataTables CSS to apply
to this table even though it is not a DataTable.

To test, apply the patch, go to Lists, and view any list with multiple
titles attached.

 - The list should be sorted by default according to the list's
   settings, and the arrow in the header row should correctly reflect
   the sorting column and direction.
 - Test re-sorting the table by each of the different sortable columns,
   confirming each time that the sorting arrows are correct.

Signed-off-by: Maryse Simard <maryse.simard@inlibro.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Martin Renvoize <martin.renvoize@ptfs-europe.com>