Log Message:
Update Sylpheed to 0.9.4, main changes are:

    * The performance of the operation of IMAP4 folders, such as
      move,copy, delete and mark, has been greatly improved.
    * The contents of IMAP4 folders are now always synchronized with the
      server.
    * Message flags are now properly taken over when copying messages
      into IMAP4 folders from others.
    * The CRAM-MD5 authentication mechanism has been supported for
      IMAP4rev1.
    * Message move, copy and delete are now possible while receiving
      mails.
    * The non-blocking SSL can be turned off as a workaround for the
      connection problem.
    * The bug that ran into infinite loop if connection was closed by
      remote host has been fixed.
    * The configuration files will not be overwritten on startup
      anymore.