Load promises polyfill from a script tag

So all JS code can assume promises work, without needing to require it.

IPython/html/static/base/js/utils.js

@@ -5,7 +5,6 @@ define([
     'base/js/namespace',
     'jquery',
     'codemirror/lib/codemirror',
-    'es6promise',
 ], function(IPython, $, CodeMirror){
     "use strict";
     

IPython/html/templates/page.html

@@ -14,6 +14,7 @@
     <link rel="stylesheet" href="{{ static_url("style/style.min.css") }}" type="text/css"/>
     {% endblock %}
     <link rel="stylesheet" href="{{ static_url("custom/custom.css") }}" type="text/css" />
+    <script src="{{static_url("components/es6-promise/promise.min.js")}}" type="text/javascript" charset="utf-8"></script>
     <script src="{{static_url("components/requirejs/require.js") }}" type="text/javascript" charset="utf-8"></script>
     <script>
       require.config({
@@ -30,7 +31,6 @@
             moment: "components/moment/moment",
             codemirror: 'components/codemirror',
             termjs: "components/term.js/src/term",
-            es6promise: 'components/es6-promise/promise.min',
             contents: '{{ contents_js_source }}',
           },
           shim: {