Convert everything to safe HTML

Summary: Sgrepped for `"=~/</"` and manually changed every HTML.

Test Plan: This doesn't work yet but it is hopefully one of the last diffs before Phabricator will be undoubtedly HTML safe.

Reviewers: epriestley

CC: aran, Korvin

Maniphest Tasks: T2432

Differential Revision: https://secure.phabricator.com/D4927

src/applications/project/controller/PhabricatorProjectMembersEditController.php

@@ -112,7 +112,7 @@ final class PhabricatorProjectMembersEditController
     $panel->setHeader($header_name);
     $panel->setWidth(AphrontPanelView::WIDTH_FORM);
     $panel->appendChild($form);
-    $panel->appendChild('<br />');
+    $panel->appendChild(phutil_tag('br'));
     $panel->appendChild($faux_form);
 
     $nav = $this->buildLocalNavigation($project);