[Mimedefang] clamd support.

[jmiller at purifieddata.net]

I'm adding clamd support to my mimedefang.pl, and wanted to know if anyone
was already working on adding it to the base distribution.

If no one is working on it, I'd be happy to make some patches for all the
files and submit them. If someone's already working on distribution
support for this, I'll just hardcode my options in for now and not worry
about all the little details.

--
Josh I.