remove prism JS/CSS

huzzah, just one CSS and one JS!

ref superfeedr/assets.superfeedr.com#32

_layouts/default.html

@@ -5,7 +5,6 @@
   <meta charset="utf-8">
   <meta name="viewport" content="width=device-width, initial-scale=1.0">
   <link rel="stylesheet" href="//assets.superfeedr.com/assets/css/global.css">
-  <link rel="stylesheet" href="/css/prism.css">
   <link href="//fonts.googleapis.com/css?family=Source+Sans+Pro:300,400,600,700,400italic|Source+Code+Pro:400,600" rel="stylesheet" type="text/css">
   <link rel="shortcut icon" href="/favicon.png">
 </head>
@@ -112,9 +111,6 @@
     </footer>
 
   </div>
+  <script src="//assets.superfeedr.com/assets/js/global.js"></script>
 </body>
-<script src="//assets.superfeedr.com/assets/js/global.js">
-</script>
-<script src="/js/prism.js">
-</script>
 </html>