Fixing reference to new Python-3 compatible version
Fixing encoding problems for Python 3

TIL that 'NTLM %s' % b'really long bytestring' == "NTLM b'really long bytestring'". I mean, it makes sense once I look at it.

IRL tested against a real Exchange server and verified I can authenticate and hit the API for results.
Fixing test server so it works with Python 3
Merge pull request #52 from trustrachel/master

Python 3 compatibility