PROCESS USER/FILE REQUESTS TO UPDATE PARAMETERS

   expo *update_xxx_params_from_keyval(examples *exams,
                                       char *params,
                                       char *key,dtvalue *dt)

An optional function.  If both
mk_aform_from_xxx_params and
update_xxx_params_from_keyval are defined,
then the user will be able to edit the
parameters and to load parameters from a
file.