Bug 7557: Change hardcoded routing list note into a system preference

Bug 7557: Change hardcoded routing list note into a system preference

Adds a new system preference RoutingListNote under the Serials tab.

The note will display above the note from the subscription and replace
the current hardcoded note:

"Notes: Please return this item promptly as others are waiting for it."

The patch adds unique ids to all notes and the note in general, so it
can be styled using CSS.

Also corrects the routing slip template to follow the HTML4 rule.

Update 2012-03-12: Fixed problem in updatedatebase.