(pmail-forwarded-attr-index): Doc fix.

(pmail-forwarded-attr-index): Doc fix.
(pmail-resent-attr-index): New variable.
(pmail-attr-array): Add r for resent.
(pmail-add-mbox-headers): Make 8 attributes.
(pmail-set-attribute): Extend attribute line if necessary.

(pmail-widen): New command.
(pmail-mode-map): o is pmail-output, C-o is pmail-output-as-seen,
(pmail-mode-map): c-w is pmail-widen.
(pmail-change-major-mode-hook): Do nothing unless buffer-swapped-with.
(pmail-show-message): Downcase character-coding.