Time for 2.3.13?

[Bron Gondwana]

I just noticed that 2.3.12 was released back in April, and
there are a few fixes changes kicking around.  I've just
compared CVS HEAD to 2.3.12 using trusty old 'diff' and
it looks like the big changes are:

* sql database support
* "can not" => "cannot"
* capabilities tidy up
* cyr_virusscan


I'd also like to push the following patches upstream:

* http://cyrus.brong.fastmail.fm/patches/cyrus-skiplist-locking-rework-2.3.12.diff
  - we've discussed this one in detail in other threads,
    and people who've tested it report it working well.

* http://cyrus.brong.fastmail.fm/patches/cyrus-skiplist-safeunlock-2.3.12.diff
  - pretty trivial fix to make consistency checks safe
    against failures.  Probably pointless, but it makes
    the code nicer.

* http://cyrus.brong.fastmail.fm/patches/cyrus-always-unlink-2.3.12.diff
  - absolutely trivial patch in the style of other fixes.
    Put an "unlink" call before an open call on a file that's
    not supposed to be there in the stage area.  Just in case[tm].

* http://cyrus.brong.fastmail.fm/patches/cyrus-longwords-2.3.4.diff
  - seriously, who is doing email with a 10Mb memory machine these
    days?  We've had a query just recently on the mailing list where
    a site hit line length issues.  Let the VM handle it.

I don't think I'd push nested transactions upstream at this stage -
it works fine for me, but it's pretty experimental still!  I'm more
interested in having a robust skiplist implementation that handles
the 'foreach used first' bug.  Then if anyone asks about skiplist
issues I can just say "use 2.3.13" rather than "use 2.3.12 plus
these patches" :)

Bron.