Merge from trunk:

Merge from trunk:
2004-07-15  Yoichi NAKAYAMA  <yoichi@geiin.org>

	* elmo-archive.el (elmo-archive-folder-append-buffer): Return nil
	on failure.

2004-07-12  Yoichi NAKAYAMA  <yoichi@geiin.org>

	* elmo.el (elmo-folder-append-messages): Note on return value.
	* elmo-archive.el (elmo-folder-append-messages): Don't return
	message numbers which could not be appended.

2004-04-11  Yoichi NAKAYAMA  <yoichi@geiin.org>

	* elmo.el (elmo-folder-append-buffer): Add note on return value.
	* elmo-cache.el (elmo-folder-append-buffer): Return nil on failure.
	* elmo-localdir.el (elmo-folder-append-buffer): Ditto.
	* elmo-split.el (elmo-split-subr): Check return value of
	elmo-folder-append-buffer.

	* elmo-cache.el (elmo-folder-append-buffer): Check existence of
	message-id.