adding publish date to video-results and rss-feed

searx/templates/opensearch_response_rss.xml

       <title>{{ r.title }}</title>
       <link>{{ r.url }}</link>
       <description>{{ r.content }}</description>
+      {% if r.pubdate %}<pubDate>{{ r.pubdate }}</pubDate>{% endif %}
     </item>
     {% endfor %}
   </channel>

searx/templates/result_templates/videos.html

 
     <p>
       <h3 class="result_title"><a href="{{ result.url }}">{{ result.title|safe }}</a></h3>
+      {% if result.publishedDate %}<p class="published_date">{{ result.publishedDate }}</p>{% endif %}
       <a href="{{ result.url }}"><img width="400px" src="{{ result.thumbnail }}" title={{ result.title }} alt=" {{ result.title }}"/></a>
       <p class="url">{{ result.url }}</p>
     </p>

searx/webapp.py

                 else:
                     result['publishedDate'] = gettext(u'{hours} hour(s), {minutes} minute(s) ago').format(hours=hours, minutes=minutes)  # noqa
             else:
+                # TODO using right timezone
+                result['pubdate'] = result['publishedDate'].strftime('%a, %d %b %Y %H:%M:%S +0000')
                 result['publishedDate'] = format_date(result['publishedDate'])
 
     if search.request_data.get('format') == 'json':