of element identifiers and it creates a page virtual temporary
category. random.php generates a randomized list of element id visible to
the user (according to permissions) and redirects to category.php.
Major problem : elements order is in id ascending order, I don't know how to
change order when having id1,id2,id3 and id2,id3,id1 (the display order is
the same)
git-svn-id: http://piwigo.org/svn/trunk@605 68402e56-0260-453c-a942-63ccdbb3a9ee
