Updates to sieve-manage.el

[Albert Krewinkel <krewinkel@moltkeplatz.de>]

Hi all,

I tried to get sieve-manage working with my dovecot/pigeonhole server.
It didn't quite work out of the box, so I made a few adjustments to the
code.  The result is in my github-repo at
git://github.com/tarleb/gnus.git (in the "sieve" branch).

Most noticable changes:
 - Added support for starttls
 - Allowing multibyte-process buffers (couldn't get
   string-parsing/encoding working without it)
 - Slightly nicer looking code (IMHO of course)
 - An ugly workaround which I intend to fix by the end of
   next week.

Any feedback on the code or advice on how to get this upstream would be
highly appreciated.

Thanks,

Albert