fix #17

Thanks @hd719 for providing the favicon and the source code

Author: niccokunzmann

_layouts/step.html

@@ -21,6 +21,7 @@
     <link type="text/css" rel="stylesheet" href="../css/requirements.css" media="screen"/>
     <link type="text/css" rel="stylesheet" href="../css/Ubuntu.css" media="screen"/>
     <link type="text/css" rel="stylesheet" href="../css/lang-{{ language }}.css" media="screen"/>
+    <link rel="shortcut icon" href="../favicon.ico?v=2" type="image/x-icon">
     <meta charset="utf-8">
     <title>{{ page.title | escape }} - Interaktive Einführung in Reguläre Ausdrücke</title>
     <script type="text/javascript">