Modernize tag and branch controllers in Diffusion

Summary: Ref T4245. Prepares these controllers to accept alternate identifers, plus minor spacing and layout fixes.

Test Plan: Viewed tags, viewed branches.

Reviewers: chad

Reviewed By: chad

Maniphest Tasks: T4245

Differential Revision: https://secure.phabricator.com/D14941

src/applications/diffusion/application/PhabricatorDiffusionApplication.php

@@ -64,7 +64,7 @@ final class PhabricatorDiffusionApplication extends PhabricatorApplication {
           '(?:query/(?P<queryKey>[^/]+)/)?' => 'DiffusionPushLogListController',
           'view/(?P<id>\d+)/' => 'DiffusionPushEventViewController',
         ),
-        '(?P<callsign>[A-Z]+)/' => array(
+        '(?P<repositoryCallsign>(?P<callsign>[A-Z]+))/' => array(
           '' => 'DiffusionRepositoryController',
 
           'repository/(?P<dblob>.*)'    => 'DiffusionRepositoryController',