Log Message:
Update to Dovecot 1.0.13.

Note that the changes for the security hole fix were quite large. I tested with
several auth configurations myself and they seemed to work, but it's possible I
left a bug somewhere in there breaking someone's configuration. So make sure to
test that it works after upgrading.

Of course it would be really nice if Dovecot had a proper test suite where
testing all configurations could be automated and run before each release. I've
already started this with my imaptest tool (http://imapwiki.org/ImapTest), but
it only does IMAP tests and a lot of things are still missing. Some help would
be nice here.

	* Fixed a security hole in blocking passdbs (MySQL always. PAM, passwd
	  and shadow if blocking=yes) where user could specify extra fields
	  in the password. The main problem here is when specifying
	  "skip_password_check" introduced in v1.0.11 for fixing master user
	  logins, allowing the user to log in as anyone without a valid
	  password.

	- mail_privileged_group was broken in some systems (OS X, Solaris?)
	- IMAP THREAD: Fixed some correctness problems