Add favicon.ico

Author: Mario Flach

_includes/head.html

@@ -9,6 +9,7 @@
     <link rel="stylesheet" href="{{ "/css/main.css" | prepend: site.baseurl }}">
     <link rel="stylesheet" href="{{ "/css/center-img.css" | prepend: site.baseurl }}">
     <link rel="canonical" href="{{ page.url | replace:'index.html','' | prepend: site.baseurl | prepend: site.url }}">
+    <link rel="shortcut icon" href="{{ "/favicon.ico" | prepend: site.baseurl }}">
 
     <meta name="twitter:card" content="summary" />
     <meta name="twitter:site" content="@{{ site.twitter_username }}" />