-remusr
template: pers?clnt=<name|pass>&com=remusr[&usr=<usr_1>&usr=...]
          Order of query params is not important. The 'usr'
          query parameters are optional.
descript: removes all records specified by 'usr' query
          parameters. If no matching records are found
          no records will be deleted (200 OK will still
          be returned). If no 'usr' query parameters exist,
          the records for all users will be deleted. If the
          error code 401 is returned then no record has
          been deleted.
example : pers?clnt=name|pass&com=remusr&usr=john&usr=kostas
          pers?clnt=name|pass&com=remusr   (deletes everything 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>
          Note that the 'number of relevant rows' is not the
          number of removed users. The removed users are given
          by : (deleted rows / number of features).
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.
          Note that if a user is to be removed from the personal mode,
          the requests 'remddt' and 'remndt' should be called to remove
          decay data and numeric data respectively, together with the
          request 'remusr' to remove user features.