* wl-vars.el (wl-message-use-header-narrowing): New user option.

* wl-vars.el (wl-message-use-header-narrowing): New user option.

* wl-summary.el (wl-summary-toggle-mime): Treat numeric prefix
argument `5'.

* wl-message.el (wl-message-display-no-merge-p): New function.
(wl-message-buffer-display): Check whether the message is
reassembled and follow the API change.

* elmo-mime.el (elmo-mime-entity-reassembled-p): New method.
(elmo-mime-entity-fragment-p): New function.
(mime-elmo-buffer-entity): Added slot `reassembled'.
(elmo-message-mime-entity): Added 4th argument `reassemble'.
(elmo-message-mime-entity-internal): New function (renamed from
`elmo-message-mime-entity').
(elmo-mime-inherit-field-list-from-enclosed): New constant.
(elmo-mime-make-reassembled-mime-entity): New function.
(elmo-message-reassembled-mime-entity): Ditto.
(elmo-mime-collect-message/partial-pieces): Ditto.