Add Route::set() override - set <args> regex and remove <controller> underscores
Then, clean up routes in bootstrap, rest/init, and tag/init.
Refactor how Theme::$is_admin is set - no longer need Route filter to do it.
Add @todo note to Watermark_Installer - remove unused DB table.
Merge pull request #385 from shadlaws/fixes_20130607

Fixes 20130607