Make inline comment preview work in Diffusion

Summary: created a PhabricatorInlineCommentPreviewController so controllers in Diffusion and Differential respectively just have to handle the URI mapping and data loading like good little controllers.

Test Plan:
left inline comments on commits, deleted inline commits, submitted inline comments -- all worked well
did the same on some diffs

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Maniphest Tasks: T1176

Differential Revision: https://secure.phabricator.com/D3034

src/aphront/configuration/AphrontDefaultApplicationConfiguration.php

@@ -257,7 +257,11 @@ class AphrontDefaultApplicationConfiguration
           'tags/(?P<dblob>.*)'          => 'DiffusionTagListController',
           'branches/(?P<dblob>.*)'      => 'DiffusionBranchTableController',
         ),
-        'inline/(?P<phid>[^/]+)/' => 'DiffusionInlineCommentController',
+        'inline/' => array(
+          'edit/(?P<phid>[^/]+)/'    => 'DiffusionInlineCommentController',
+          'preview/(?P<phid>[^/]+)/' =>
+            'DiffusionInlineCommentPreviewController',
+        ),
         'services/' => array(
           'path/' => array(
             'complete/' => 'DiffusionPathCompleteController',