Add support for HTTPConnection.getresponse(buffering=True)

[pkwarren]

Python 2.7 has added support for buffering when reading from HTTP connections, which leads to a significant improvement in HTTP client performance.

See: http://bugs.python.org/issue4879

It looks like the only changes required would be in HTTPConnectionPool._make_request, passing buffering=True to the getresponse() call on Python 2.7 and later.

urllib2.py does the following:

try:
    r = h.getresponse(buffering=True)
except TypeError: #buffering kw not supported
    r = h.getresponse()

[shazow]

Hmm interesting. As far as I understand this, it should only impact reading the headers, correct?

I'm happy to accept a patch for this if you'd like to send a pull request. :)