Made footer a template block

Made it easier to disable footer when does not need it.

app/templates/base.html

@@ -23,6 +23,8 @@
 		<script src="{{bootstrap_find_resource('jquery.js', cdn='jquery')}}"></script>
 		<script src="{{bootstrap_find_resource('js/bootstrap.js', cdn='bootstrap')}}"></script>
 		{% endblock %}
-		{% include "footer.html" %}
+		{% block footer %}
+			{% include "footer.html" %}
+		{% endblock %}
 	</body>
 </html>