Add links to next and previous post

_layouts/post.html

@@ -7,6 +7,16 @@ layout: default
   <time datetime="{{ page.date | date_to_xmlschema }}" class="post-date">{{ page.date | date_to_string }}</time>
   {{ content }}
   <hr>
+
+	<div class="PageNavigation">
+	  {% if page.previous.url %}
+		<a class="prev" href="{{page.previous.url}}">&laquo; {{page.previous.title}}</a>
+	  {% endif %}
+	  {% if page.next.url %}
+		<a class="next" href="{{page.next.url}}">{{page.next.title}} &raquo;</a>
+	  {% endif %}
+	</div>
+
   {% include google_adsense.html %}
   <hr>
   {% include disqus.html %}