Bug 28764: Parse direction parameter in public list view

This patch adds a check for a 'direction' paramter in list sorting.

It maintains the existing syntax for sorting 'sortfield=field:direction'
but adds support for the form used in paginations and more commonly thtoughout
Koha' sortfield=field&direction=direction'

To test:
1 - Create a public list
2 - Add enough items to generate two pages (40 worked for me)
3 - View the list and enforce sorting by date added descending:
    sortfield=dateadded:desc
4 - Note the titles shown
5 - Click to second page using the pagination bar
6 - Note the same titles are shown, in a reversed order
7 - Apply patch
8 - repeat 305
9 - Second page is sorted correctly!

Signed-off-by: Owen Leonard <oleonard@myacpl.org>

Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>

Signed-off-by: Jonathan Druart <jonathan.druart@bugs.koha-community.org>

opac/opac-shelves.pl

@@ -267,6 +267,7 @@ if ( $op eq 'view' ) {
                 $sortfield = $shelf->sortfield;
                 $direction = 'asc';
             }
+            if( defined( $query->param('direction') ) ){ $direction = $query->param('direction'); }
             $sortfield = 'title' if !$sortfield or !grep { $_ eq $sortfield } qw( title author copyrightdate itemcallnumber dateadded );
             $direction = 'asc' if !$direction or ( $direction ne 'asc' and $direction ne 'desc' );
             my ( $page, $rows );