Use absolute path for icon so it doesnt break on subdirectories

Author: azonenberg

_layouts/default.html

@@ -33,7 +33,7 @@
             {% endif %}
 
             <h1 id="project_title">
-                <img src='images/logo.png' width='64' height='64' class='logo'/>
+                <img src='/images/logo.png' width='64' height='64' class='logo'/>
                 {{ site.title | default: site.github.repository_name }}
             </h1>
             <h2 id="project_tagline">{{ site.description | default: site.github.project_tagline }}</h2>