Removes deprecated hosts support.

Fixes a syntax error in chat example.
Adds User profile scraping and room info scraping, with simple tests.

Moves some logic from client to room.

Adds simple docstrings with epydoc annotations to public fields and
methods of Client. Also adds epydoc as a dev dependency, and adds
`make epydocs`.

It probably isn't necessary to add this documentation to our internal
methods, and I won't bother with browser for now, but I think it's
useful to have for our user-friendly interface. (Both for users directly
and through IDEs that recognize the type annotations, like PyCharm CE.)

resolves #52 - let's forget about slugs and message sets for now. We can
reply to messages and a weak set of current messages might be pointless.

ref #65, #43 - event/message iterators/contexts are still outstanding.