This is in preparation for the new default template. This also updates the tpl_actiondropdown() to use most of them.

removed 'view original' button from new media manager again (was added in b8a84c03) and made a link around the image instead, as that is a more minor change (as it should be during the RC phase) and is what was originally planned

Template authors need to update their _mediamanager.css

This could happen if a sidebar is rendered before the page (populating
$TOC) and the page itself had no own TOC (no headers).

show accesskey also on actionlink title and add accesskey parameter only if a key is defined (FS#2226)