Log Message:
Update to:

* 2.2.3 (stable)

    * The sorting of the result of the query search was enabled.
    * The printing of messages now follows the state of 'Show all headers'.
    * Relative path is allowed for signature files.
    * The To, Cc, and Bcc button of the address book are now always enabled.
    * The window position of the address book is now preserved.
    * The toggle of the Cc entry on the composition window was enabled.
    * The appearance of the address book was modified.
    * Unix: The support of metamail command was removed, and it was replaced
      with the alternative implementation.
    * Win32: libwimp.dll was updated, and the appearance of the UI was
      improved.
    * Win32: zlib1.dll was updated.
    * Win32: The application icon was updated.
    * Win32: The unnecessary message catalog files were removed to reduce the
      archive size.