Make some of torproject.org's onion services into single onion services

https://blog.torproject.org/blog/whats-new-tor-0298#comment-226818 asks "Which of the services listed in onion.torproject.org (http://yz7lpwfhhzcdyc5y.onion/) are single hop services?"

I think that's a great question. I think the answer right now is "none", but we could change that. Should we?