Fix result enumerator stream and feed

This fixes two bugs, one in Status.feed, and one in Status.stream, both completely different problems, but both with the same effect, the server never terminated the response when the enumerator was done.

With Status.stream, the enumerator was being fed into the response iteratee using `|>>` instead of `|>>>`.

With Status.feed, since no content length header was being set, the only way to terminate the response is to close the connection, but the connection was only being closed if keep alive wasn't set (keep alive is the default for HTTP/1.1).

Two trivial tests have been added to test these scenarios.