#88 Fix AttributeError with NTLM authentication.

The below has fixed a couple of NTLM authentication issues that I have been having. I don't control the NTLM servers so I am not completely sure that they are returning proper data, but the included patch originally mentioned by cube in this SO article, http://stackoverflow.com/questions/13649964/python-mechanize-with-ntlm-getting-attributeerror-httpresponse-instance-has-no, has fixed the issue for me.