Atom and RSS templates reference incorrect blog URL

[OJ]

Both of the feed templates, RSS and Atom, reference bf.config.blog.url which I believe is incorrect (and hence is coming through as None in the generated feed).

They should instead reference bf.config.site.url.

I would have put a pull request together for this but I've butchered my version of blogofile a bit and it might have been more work :)

Cheers!