Put the requisite resources in the <header>

We use the stock `initHighlightingOnLoad` method in lieu of better
techniques like WebWorkers for maximum compatibility. We don't need to
do a ton of highlighting on the blog anyways.

Author: ecstatic-morse

templates/headers.hbs

@@ -27,6 +27,11 @@
 <link rel="stylesheet" href="/styles/vendor.css"/>
 <link rel="stylesheet" href="/styles/fonts.css"/>
 <link rel="stylesheet" href="/styles/app.css"/>
+<link rel="stylesheet" href="/styles/highlight.css"/>
+
+<!-- scripts -->
+<script src="/scripts/highlight.js"></script>
+<script>hljs.initHighlightingOnLoad();</script>
 
 <!-- favicon -->
 <link rel="apple-touch-icon" sizes="180x180" href="/images/apple-touch-icon.png">