* wl-util.el (wl-filter-associations): New function.
* wl-spam.el (wl-spam-undecided-folder-list): New user option.
(wl-spam-ignored-folder-list): Ditto.
(wl-spam-ignored-folder-regexp-list): Set default value as nil.
(wl-spam-string-member-p): New function.
(wl-spam-domain): Use it.
(wl-spam-split-numbers): New function.
(wl-spam-apply-partitions): Ditto.
(wl-spam-register-spam-messages): Use `folder' instead of
`wl-summary-buffer-elmo-folder'.
(wl-spam-register-good-messages): Ditto.
(wl-summary-exec-action-spam): Decide a domain by real folder of
message.
(wl-summary-exec-action-refile-with-register): Likewise.
* elmo-util.el (elmo-string-member): Allow symbol element in list.