Enable MathJax for live preview.

lib/gollum/frontend/public/gollum/livepreview/index.html

@@ -37,5 +37,6 @@ var require = {
 <script src="js/jquery/jquery-1.7.2.min.js" type="text/javascript" charset="utf-8"></script>
 <script src="js/debounce/jquery.ba-throttle-debounce.js" type="text/javascript" charset="utf-8"></script>
 <script src="js/livepreview/livepreview.js" type="text/javascript" charset="utf-8"></script>
+<script src="https://c328740.ssl.cf1.rackcdn.com/mathjax/latest/MathJax.js?config=TeX-AMS-MML_HTMLorMML" type="text/javascript" charset="utf-8"></script>
 </body>
 </html>

lib/gollum/frontend/public/gollum/livepreview/js/livepreview/livepreview.js

@@ -242,6 +242,7 @@ var makePreviewHtml = function () {
   // Update the text using feature detection to support IE.
   // preview.innerHTML = text; // this doesn't work on IE.
   previewSet( text );
+  MathJax.Hub.Typeset( content );
 
   // highlight code blocks.
   var codeElements = preview.getElementsByTagName( 'pre' );