erp5_core: html viewer define the interface

product/ERP5/bootstrap/erp5_core/SkinTemplateItem/portal_skins/erp5_core/gadget_html_viewer.html.html

@@ -4,6 +4,7 @@
     <meta charset="utf-8">
     <meta name="viewport" content="width=device-width, initial-scale=1">
     <title>HTML viewer gadget</title>
+    <link rel="http://www.renderjs.org/rel/interface" href="interface_editor.html">
     <link rel="stylesheet" href="gadget_html_viewer.css">
     <script src="rsvp.js"></script>
     <script src="renderjs.js"></script>