More dl's and dd's. Rather than replicate them in every sub-class,
let's just put them in one place.

I modified public.php to use the new UI framework. Since the Action
class isn't functional yet, I don't know if it works.

I took some of the functionality, like the public tabs nav and the
feeds list, and made them widgets.

I also moved the navigation from common_navigation() to a method of
Action.