Add missing jQuery reference

Author: Rafael J. Staib

index.html

@@ -21,6 +21,7 @@
         <link rel="stylesheet" type="text/css" href="stylesheets/pygment_trac.css" media="screen">
         <link rel="stylesheet" type="text/css" href="stylesheets/print.css" media="print">
 
+        <script src="javascripts/jquery-1.9.1.min.js"></script>
         <!--[if lt IE 9]>
         <script src="//html5shiv.googlecode.com/svn/trunk/html5.js"></script>
         <![endif]-->