* wl-folder.el (wl-folder-check-one-entity): Use `new' value of diff.

* wl-folder.el (wl-folder-check-one-entity): Use `new' value of diff.

* wl-util.el (wl-biff-check-folder-async-callback): Ditto.

* mmimap.el (mmimap-entity-section): If node-id is nil, return "0".

* elmo.el (elmo-diff-new): New inline function.
(elmo-diff-unread): Ditto.
(elmo-diff-all): Ditto.

* elmo-imap4.el (elmo-imap4-server-diff-async-callback-1): Get recent
value from responseb.
(elmo-imap4-folder-diff-plugged): Ditto.
(elmo-imap4-server-diff-async): Added recent argument.
(elmo-server-diff-async): Ditto.
(elmo-imap4-folder-diff-plugged): Ditto.