Enable image macros on the wiki

Summary: D2230 did the heavy lifting spoken of in the comment this diff deletes. Also remove 'macro' => false.

Test Plan: Added an image macro to a wiki document and it showed up

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Maniphest Tasks: T1023

Differential Revision: https://secure.phabricator.com/D2668

src/applications/markup/PhabricatorMarkupEngine.php

@@ -41,10 +41,6 @@ class PhabricatorMarkupEngine {
 
   public static function newPhrictionMarkupEngine() {
     return self::newMarkupEngine(array(
-      // Disable image macros on the wiki since they're less useful, we don't
-      // cache documents, and the module is prohibitively expensive for large
-      // documents.
-      'macros' => false,
       'header.generate-toc' => true,
     ));
   }