Bug 21693: Clean up checkout notes template

Bug 21693: Clean up checkout notes template

This patch modifies the checkout notes template to help compliance with
coding guidelines and interface patterns:

 - Convert to Bootstrap grid
 - Improve DataTables configuration
 - Put buttons into a toolbar and move above selection links

Also corrected: Minor markup error in circ-nav.inc

To test, apply the patch and enable the AllowCheckoutNotes system
preference. Add a few checkout notes via the OPAC.

 - Go to Circulation -> Checkout notes.
   - Confirm that the page looks correct at various browser widths.
   - Confirm that the first and last columns of the table of notes are
     not sortable.
   - The table should be sorted by default by title.
   - Title sorting should ignore articles "a," "an," and "the."
   - Test with the CircSidebar preference both on and off.
     - With CircSidebar turn on, the checkout notes menu item in the
       left hand sidebar should show a count of checkout notes.

Signed-off-by: Pierre-Marc Thibault <pierre-marc.thibault@inLibro.com>
Signed-off-by: Katrin Fischer <katrin.fischer.83@web.de>
Signed-off-by: Nick Clemens <nick@bywatersolutions.com>