Fix typo in quickstart doc
When sock file close, underlying socket not closed

It appears that in Python 3.4, closing a socket file doesn't close the
underlying socket. I'm not sure if this is a bug or not, but we now
close the underlying socket after the file is closed.
Only send Describe message after prepare

We used to send both a Describe statment and a Describe portal, now we
just send a Describe statement.

Also add testing for Python 3.4