allow this behavior when WSGIRequest.decode_param_names is enabled

  contents to unicode on the fly. Any FieldStorages encountered are cloned with
  their name and filename fields decoded
o Added WSGIRequest.charset and errors. When charset is set, WSGIRequest's
  params/GET/POST return UnicodeMultiDicts. charset and errors inherit their
  default values from the WSGIRequest.defaults StackedObjectProxy dict
o deprecated wsgiwrappers.settings: use wsgiwrappers.WSGIResponse.defaults
  instead
o allow WSGIResponse to let unicode responses pass through when no encoding is
  set (instead of defaulting to iso-8859-1). In case someone wants to deal
  with unicode later in their WSGI stack

  argument dictionary where values corresponding to a given
  key are returned in a list

If you used the all_as_list argument to parse_formvars that was
removed w/o backwards compatibility, you can convert your code
to add .dict_of_lists() on the return value of parse_formvars
as a replacement.