Log Message:
Update to 0.623

Upstream changes:
0.623 Thu Jun 13 23:29:52 2013 +1000    <joe@kafsemo.org>
        - Fix a memory leak introduced in 0.620.
        - Avoid issue with implicit stringification.

0.622 Tue May 28 23:02:56 2013 +1000    <joe@kafsemo.org>
        - Fix bug where output is an IO::Scalar.

0.621 Sun Apr 14 22:42:38 2013 +1000    <joe@kafsemo.org>
        - Include selfcontained_output.t in the distribution.

0.620 Sun Apr 14 22:20:33 2013 +1000    <joe@kafsemo.org>
        - Allow OUTPUT => 'self' (#81327).