Add footer option

[wstomv]

Given that the header and the tab lines are customizable, it would be nice to have a customizable footer as well.

My main application would be to sandwich the tab lines with list/table begin/end tags.
Eg.

Header: <ul>
Tab line: <li>{window-id}: <a href="{url}">\n{title}\n</a></li>
Footer: </ul>

I guess, I could just drop the closing </ul> and live with that (most browsers won't mind).

And, using <p> instead of <li> also gives reasonable output.