* wl-summary.el (wl-summary-mark-as-read-internal): New inline

* wl-summary.el (wl-summary-mark-as-read-internal): New inline
function.
(wl-summary-mark-as-read, wl-summary-mark-as-unread): Use it.
(wl-summary-update-mark): Enclose with save-excursion.
(wl-summary-mark-as-read-internal): Fixed last change.
(wl-summary-mark-as-important): Use 3rd argument of
elmo-folder-unmark-important, elmo-folder-mark-as-important;
Don't use elmo-msgdb-set-mark.
(wl-summary-redisplay-internal): If msgdb flag is already read,
just update the mark on buffer.

* elmo.el (elmo-message-set-mark): Abolish.

* elmo-msgdb.el (toplevel): Added comment.
(elmo-msgdb-set-mark): Abolish.
(elmo-load-msgdb): Added 4th element `path'.
(elmo-msgdb-append): Follow the change above.
(elmo-msgdb-clear): Ditto.
(elmo-msgdb-delete-msgs): Ditto.
(elmo-msgdb-get-path): New inline function.
(elmo-msgdb-set-path): Ditto.
(elmo-flag-table-filename): New variable.
(elmo-flag-table-load): New function.
(elmo-flag-table-set): Ditto.
(elmo-flag-table-save): Ditto.
(elmo-msgdb-get-field-value): Abolish.
(elmo-msgdb-overview-get-entity-by-number): Ditto.