-remdcy
template: pers?clnt=<name|pass>&com=remdcy[&grp=<ftr_group_1>&grp=...]
          Order of query params is not important. The 'grp'
          query parameters are optional.
descript: removes all decay group records specified by 'grp'
          query parameters. If no matching records are found
          no records will be deleted (200 OK will still be
          returned). If no 'grp' query parameters exist, the
          records for all feature groups will be deleted. If
          the error code 401 is returned then no record has
          been deleted. Note that for initializing the Personal
          Mode DB (removing all records in all tables) this
          request (the 'delete everything' version) must be
          used together with 'remftr', as the 'remftr' does not
          affect the table 'decay_groups'.
example : pers?clnt=name|pass&com=remdcy&grp=page10&grp=advertisements.clothing
          pers?clnt=name|pass&com=remdcy   (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>
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 an important reason why this request does not
          delete decay data as well (the timestamped user-feature
          interactions with features that belong to the specified
          groups) is that a feature name may correspond to more
          than one groups (eg. page10.banners.banner2 corresponds
          to both page10 and page10.banners groups).