<!doctype html>
<html lang="en-US">
  <head>
    <meta charset="utf-8">

    <!--[if IE]>
      <script src="https://cdnjs.cloudflare.com/ajax/libs/es5-shim/4.5.9/es5-shim.min.js"></script>
      <script src="https://cdnjs.cloudflare.com/ajax/libs/es5-shim/4.5.9/es5-sham.min.js"></script>
    <![endif]-->

    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.6/css/bootstrap.min.css"/>
  </head>

  <body>
    <div id="root">
    </div>

    <script src="bundle.js"></script>
  </body>
</html>

<!doctype html>
<html lang="en-US">
  <head>
    <meta charset="utf-8">
    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/twitter-bootstrap/3.3.6/css/bootstrap.min.css"/>
  </head>

  <body>
    <div id="root">
    </div>

    <script src="bundle.js"></script>
  </body>
</html>

Drop the ES5 shim altogether
Drop the ES5 shim altogether

Seems we don't work on IE<11 anyway
