Allow the 'Uploaded to this post' view to be sorted, saving the resulting order as menu_order.

This functionality is designed to be backwards compatible with manual querying for attachments by menu_order.

props koopersmith.
see #22607.



git-svn-id: https://core.svn.wordpress.org/trunk@22967 1a063a9b-81f0-0310-95a4-ce76da25c4cd