Log Message:
Update to 2.10.0.

* Changes in 2.10.0 from 2.8.1

** You can alter the format of summary lines.
   Specify format by wl-summary-line-format. If you want to change ones
   according to folder names, use wl-folder-summary-line-format-alist.
** Save format for the draft folder has been changed. Messages are encoded
   before saved by wl-draft-save.
** elmo-split is newly established.
** Buffer prefetch works fine now. Messages of the number specified by
   wl-message-buffer-prefetch-depth are loaded into buffer in advance.
** elmo-dop-queue-flush flushes queue that concerns plugged folder.
** Starting Wanderlust on the new frame is possible now. Set as
   (autoload 'wl-other-frame "wl" "Wanderlust on new frame." t)
** In Folder mode, you can go into virtual folder which consists of messages
   with some specified condition (wl-folder-virtual). It is binded to "V".
** In Folder mode, you can search folders containing messages with some
   specified condition (wl-folder-pick). It is binded to "?".
** Now you can rename access group folders.
** Temporary marks are kept when you exit from sticky summary by q or g.
** Key bindings concerning the sticky summary have been changed.
   By C-u g, the sticky summary is destroyed as well as C-u q. In summary or
   folder mode, G opens the sticky summary.
** You can go round summary buffers by C-cC-n and C-cC-p.
** Members of the list wl-folder-hierarchy-access-folders is now some REGEXP
   for access group names instead of exact group names.
** In header part of the draft buffer C-a brings cursor to the beginning of
   the line or the beginning of the header body.
** You can send encapsulated blind carbon copies. Its default field name is
   "Ecc:".
** C-c C-y (Draft) can cite region of the message.
   It affects if transient-mark-mode (Emacs) or zmacs-regions (XEmacs) is
   Non-nil and the region is active.
** You can delete a part from multipart message.
   It is binded as "D" in message buffer.
** You can easily configure server settings to post news article.
   Set wl-nntp-posting-config-alist appropriately. See info for an example.
** You can specify some function in wl-draft-reply-with-argument-list etc.
   for setting the recipients in draft by the return value of it.
** The interface of the function wl-draft has been changed.
   The initial set of headers are handed as an association list.
** The uses of wl-generate-mailer-string-function has been changed.
   Specify a function which returns some string to appear in User-Agent header.
** Many bug fixes.