adds prev + next buttons on page

s/item.tpl.html

@@ -19,7 +19,7 @@
       <img src="{{ dest }}" style="max-width: 1024px" />
     {% endif %}
   </div>
-  <div class="controls">controls f&uuml;r vor und zur&uuml;ck :^)</div><br />
+  <div class="controls">{% if prev != null %}<a href="/{{ prev }}">Prev</a>{% endif %} {% if next != null %}<a href="/{{ next }}">Next</a>{% endif %}</div><br />
   <div class="info">
     <span class="src">src: <a href="{{ src }}" target="_blank">{{ src }}</a></span><br />
     <span class="dest">dest: {{ dest }}</span><br />