1. Fixed cache problem that caused the pageset configuration page to blow up. 2. Rather than bomb on duplicate tab and url names for pages, which can arise when deleting then adding pages as well as admin-provided names, "uniquify" them. The admin can, of course, then rename them to something more reasonable if they want.
Allow for localization of tab names. Doesn't quite work the way we want as the name is localized when displayed in the edit box (should look at using ad_form but it's not simple ...)