* wl-summary.el (wl-summary-mark-as-read): Set msgdb mark only when

* wl-summary.el (wl-summary-mark-as-read): Set msgdb mark only when
it is differed.

* elmo-util.el (elmo-disk-usage): Return 0 if invalid file attribute.

* elmo-msgdb.el (elmo-msgdb-create-overview-from-buffer): Avoid
changing default value of default-mime-charset.
(elmo-msgdb-create-overview-from-buffer): Remove TAB character.

* elmo-imap4.el (elmo-folder-open): Fixed NO response check.

* elmo-dop.el (elmo-dop-queue-merge-method-list): New variable.
(elmo-dop-queue-merge): Use elmo-dop-queue-merge-method-list
instead of elmo-dop-queue-method-name-alist to check merging queue.
(elmo-folder-delete-messages-dop): Delete from queue if negative
message number.
(elmo-folder-append-buffer-dop-delayed): Treat as success if queue
file is already removed.