Add ExtensionUtils to root require context

Author: jasonsanjose

src/brackets.js

@@ -79,6 +79,7 @@ define(function (require, exports, module) {
     require("debug/DebugCommandHandlers");
     require("view/ViewCommandHandlers");
     require("search/FindInFiles");
+    require("utils/ExtensionUtils");
 
     // TODO: Issue 949 - the following code should be shared