-remftr
template: ster?clnt=<name|pass>&com=remftr&[str=<str>&]ftr=<ftr_pattern_1>&ftr=...
          Order of query params is not important. Query param
          'str' is optional.
pattern : * | name[.*], where name is a path expression.
descript: removes all records with features matching the 
          feature pattern(s), for the specified stereotype(s):
          either for all stereotypes if 'str' is omitted, or
          for a single stereotype. If no (stereotype, feature)
          in DB matches the patterns, no record will be deleted
          (200 OK will still be returned). If the error code
          401 is returned then no records have been deleted.
example : ster?clnt=name|pass&com=remftr&str=guest&ftr=lang.*&ftr=interested
          ster?clnt=name|pass&com=remftr&ftr=education
          ster?clnt=name|pass&com=remftr&ftr=*   (deletes all rows in table)
returns : 200 OK, 401 (fail, request error), 501 (fail, server error)
200 OK  : in this case the response body is as follows
          <?xml version="1.0"?>
          <?xml-stylesheet type="text/xsl" href="/resp_xsl/rows.xsl"?>
          <result>
          <row><num_of_rows>number of relevant rows</num_of_rows></row>
          </result>
comments: the reference to the xsl file allows to view results
          in a web browser. In case the response body is handled
          directly by an application and not by a browser, this
          reference to xsl can be ignored.