Log Message:
Update to 2.4.0.

* New features

  o Toolbar
    + The customization of the toolbars was implemented.
    + 'Prev', 'Print', 'Address', 'Prefs', 'Account', 'Not junk',
      'Search' and 'Stop' button was added to the toolbars.
    + The overflow menu for the toolbars was added.
    + The option to place toolbar labels at the right of icons was added.
  o Address book
    + Copy and paste of persons in the address book was enabled.
    + In the address book, the import of CSV and Tab-separated text file
      was enabled.
  o The automatic filtering of IMAP4 on receive operation was enabled.
  o The option to toggle the window on the trayicon click was added.

* Feature improvements

  o Junk mails are now filtered when incorporating from local spool.
  o The width of toolbar buttons was reduced when the labels are displayed.
  o The checking of remote folders doesn't abort with non-fatal errors now
    except for network failure.
  o Close button was added to the address book dialog.
  o In-Reply-To header was supported in mailto URL.
  o An error message is displayed now when the decryption of PGP encrypted
    messages failed.
  o 'Within 1 day' and 'Last 5 days' was added to the quick search rule.
  o The toolbar style switch was added to the toolbar context menu.
  o The limitation of the nesting level of MIME structure was relaxed.
  o A margin for text was added to the composition window.
  o An error dialog is displayed if the execution of junk filter command fails.
  o The overwrite confirmation of the file selection dialog was improved.
  o The file copy and move operation were optimized.
  o The included Japanese manual was updated.
  o Unix: Symbolic links are now also scanned when scanning MH folders.

* Bugfixes

  o The problem that the width of the folder view was not saved when the
    main window was maximized was fixed.
  o The crash when verifying signed messages with popup window was fixed.
  o The crash on exit when the order of summary columns were modified by
    DnD was fixed.
  o The wrong handling of quotation in multi-byte strings on MIME header
    encoding was fixed.
  o The behavior of 'Go to next unread' with changing folders was fixed.
  o Several bugs of the search dialog were fixed.
  o Several bugs of the address book were fixed.
  o The crash on the cancellation of sending or receiving was fixed.
  o Unix: The bug that the window was kept being skipped from window list
    after it became visible with window shading or switching workspaces.

* Changes from 2.4.0rc

  o Invalid APOP timestamp is rejected now (CVE-2007-1558).
  o The configuration file is written out after the toolbar is customized.