Log Message:
Update sylpheed to 2.0.2. Main changes are:

    * The auto detection of Japanese encoding now supports UTF-8
      encoding.
    * The number of messages to be copied at a time on IMAP4 was
      limited to prevent timeout error.
    * When executing IMAP4 operations which take long time, its
      progress is now displayed on the statusbar, and the UI is
      periodically updated.
    * The selected row of the summary view will be kept when the state
      of thread display is changed.
    * The code conversion error and line limit warning will not be
      displayed anymore when saving as draft.
    * A bug that prevented the expander of the folder tree of the
      address book working was fixed.
    * A bug in which message/rfc822 attachments were broken when
      pgp-signed was fixed.