[IronPython] Switching Mailing List to CodePlex

[Sanghyeon Seo]

> If you've got a strong opinion about CodePlex mailing lists one way or
> another, please let me know.

I am okay with it provided that all previous links to Mailman archive
transparently redirects, forever, to the correct place.

Otherwise I am strongly against. (I probably made hundreds of links to
the archive of this mailing list, and it's only me.)

-- 
Seo Sanghyeon