Broke up the tag action into two different actions (publictagcloud and
tag). Brought it up-to-date with the new framework, but haven't fixed it
for phpcs yet.
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.
