Update Phabricator header to use FontAwesome

Summary: Updates header to use font-icons instead of images.

Test Plan: Test desktop and mobile layouts, Chrome, FF, Safari, IE.

Reviewers: btrahan, epriestley

Reviewed By: epriestley

Subscribers: Korvin, epriestley

Differential Revision: https://secure.phabricator.com/D10930

src/applications/help/application/PhabricatorHelpApplication.php

@@ -40,7 +40,7 @@ final class PhabricatorHelpApplication extends PhabricatorApplication {
       $item = id(new PHUIListItemView())
         ->setName($help_name)
         ->addClass('core-menu-item')
-        ->setIcon('info-sm')
+        ->setIcon('fa-info-circle')
         ->setAural($help_name)
         ->setOrder(200)
         ->setHref($application->getHelpURI());