Bug 11375: Improve patrons permissions display

Bug 11375: Improve patrons permissions display

This patch updates the patron permissions interface in order to
emphasize permission descriptions (which can be translated) over
permission code (which cannot).

The tree structure (and jQuery plugin) is removed, and permissions are
displayed in a table-like way. Sub-permissions are shown or hidden with
a link.

A free-text filter is added to the top for narrowing the list by
keyword.

Save and cancel buttons are now in a floating toolbar.

To test, apply the patch, regenerate the staff client CSS, and clear
your browser cache if necessary.

 - Open the "Set permissions" page for any patron.
 - Confirm that the filter works correctly to show only lines which
   match your entry
   - Note that the superlibrarian line stays visible all the time. This
     is to make it clearer that sub-permissions cannot be selected if
     superlibrarian is checked.
 - Check the superlibrarain "hint" text for clarity.
 - Test the show/hide controls.
 - Test that checking a "parent" permission displays the
   sub-permissions.
 - Test that the toolbar with Save and Cancel floats when scrolling.
 - Test that changing and saving permissions works correctly.

Signed-off-by: Maryse Simard <maryse.simard@inlibro.com>
Signed-off-by: Josef Moravec <josef.moravec@gmail.com>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>