Handle HTTP/0.9 responses.

Handle HTTP/0.9 responses.

Section 19.6 of RFC 2616 (HTTP/1.1):

   It is beyond the scope of a protocol specification to mandate
   compliance with previous versions. HTTP/1.1 was deliberately
   designed, however, to make supporting previous versions easy....

   And we would expect HTTP/1.1 clients to:

      - recognize the format of the Status-Line for HTTP/1.0 and 1.1
        responses;

      - understand any valid response in the format of HTTP/0.9, 1.0, or
        1.1.

The changes to the code do handle response in the format of HTTP/0.9.
Some users may consider this a bug because all responses with a
sufficiently corrupted status line will look like an HTTP/0.9
response.  These users can pass strict=1 to the HTTP constructors to
get a BadStatusLine exception instead.

While this is a new feature of sorts, it enhances the robustness of
the code (be tolerant in what you accept).  Thus, I consider it a bug
fix candidate.

XXX strict needs to be documented.