Finish head attribute settings.

- Add open graph meta attribute (also with twitter card, google puls, facebook)
- Split the modules with css, icon, open graph etc.

layouts/partials/header.html

@@ -14,6 +14,11 @@
                 <i class="logo-line"></i>
             </a>
             <p class="site-subtitle" itemprop="description">{{ .Site.Params.subtitle }}</p>
+            {{ with .Site.Params.customLogo }}
+            {{ if .show }}
+             <img class="custom-logo-image" src="{{ .url }}" alt="Custom Logo">
+            {{ end }}
+            {{ end }}
         </div>
         <div class="site-nav-right">
             <div class="toggle popup-trigger">