Make Differential inline comment rendering more consistent and somewhat more modern

Summary: Ref T2222. Ref T1790. I partially modernized this recently, but bring it to the mail version too.

Test Plan: See screenshots.

Reviewers: btrahan

Reviewed By: btrahan

CC: zeeg, aran

Maniphest Tasks: T1790, T2222

Differential Revision: https://secure.phabricator.com/D8294

src/infrastructure/diff/PhabricatorInlineCommentController.php

@@ -173,7 +173,7 @@ abstract class PhabricatorInlineCommentController
     // application identifier for the changeset. In Diffusion, it's a Path ID.
     $this->changesetID    = $request->getInt('changeset');
 
-    $this->isNewFile      = $request->getBool('is_new');
+    $this->isNewFile      = (int)$request->getBool('is_new');
     $this->isOnRight      = $request->getBool('on_right');
     $this->lineNumber     = $request->getInt('number');
     $this->lineLength     = $request->getInt('length');