[exim] Exim article

I've written an introductory article about setting up Exim for a Linux
magazine. It's not quite complete, but it's getting there. The latest version
is at http://www.btinternet.com/~n.s.youngman/exim.html.

If anyone would like to take a look and point out all the howlers, I would
appreciate your feedback.

Thanks

Neil Youngman