WebSearch: OpenSearch support and richer RSS
WebSearch: OpenSearch support and richer RSS

* Added OpenSearch support.

* Richer RSS output.  Also, use <dc:creator> instead of <author> tag
  when author is not an email, to have a valid feed.

tiborsimko/invenio-formatter,inveniosoftware/invenio-formatter,inveniosoftware/invenio-formatter,tiborsimko/invenio-formatter,inveniosoftware/invenio-formatter,tiborsimko/invenio-formatter