* gnus-art.el (article-decode-charset): Don't use ignore-errors when calling

* gnus-art.el (article-decode-charset): Don't use ignore-errors when calling
 mail-header-parse-content-type.
(article-de-quoted-unreadable): Ditto.
(article-de-base64-unreadable): Ditto.
(article-wash-html): Ditto.

* mm-decode.el (mm-dissect-buffer): Don't use ignore-errors when calling
 mail-header-parse-content-type and mail-header-parse-content-disposition.
(mm-find-raw-part-by-type): Don't use ignore-errors when calling
 mail-header-parse-content-type.

* mml.el (mml-insert-mime-headers): Use mml-insert-parameter to insert charset
 and format parameters; encode description after inserting it to buffer.
(mml-insert-parameter): Fold lines properly even if a parameter is segmented
 into two or more lines; change the max column to 76.

* rfc1843.el (rfc1843-decode-article-body): Don't use ignore-errors when
 calling mail-header-parse-content-type.

* rfc2231.el (rfc2231-parse-string): Return at least type if possible; don't
 cause an error even if it fails in parsing of parameters.  Suggested by
 ARISAWA Akihiro <ari(at)mbf.ocn.ne.jp>.
(rfc2231-encode-string): Don't break lines at the beginning, leave it to
 mml-insert-parameter.

* webmail.el (webmail-yahoo-article): Don't use ignore-errors when calling
 mail-header-parse-content-type.