Requests-credssp

* Changed some log messages to a debug level instead of info

* Added support for Python 3.7
* Fix version info warning msg for pub key authentication process

* Drop support for Python 3.3
* Added support for new CredSSP protocol 5 and 6, mitigates CVE 2018-0886
* Added the ability to specify a minimum CredSSP server version
* Added support for SPNEGO/Kerberos authentication over CredSSP
* Removed manual asn.1 structures and added dependency on pyasn1 for easier
code management
* Deprecated older function in HttpCredSSPAuth that should be host specific
instead of global
* Changed license to MIT from ISC
* Tidied up test suite to use py.test and added pep8 checks

* Added support for using the TLS context to encrypt payload data
* Tidied up the dependencies to set a minimum required version for pyOpenSSL and requests
* Set ordereddict to only be a dependency for Python 2.6

* Small fix for older version of pyOpenSSL don't fail when this library is loaded

Initial Commit, supports

* Full support for CredSSP using NTLM authentication
* TLSv1.2 by default, ability to use TLSv1 if flag is used