Update library to be python3.6 compatible

[jmichelsen]

No description provided.

[jmichelsen]

I know pr #32 exists to convert the repo to python3 using the 2to3 utility. I converted this manually to allow it to remain backwards compatible with python2.6 and python2.7. Cheers.

[cknave]

Thanks for the PR! Looks good aside from needing to pull in six as a requirement. Can you check this without it?

An example from http://python3porting.com/noconv.html#more-bytes-strings-and-unicode:

>>> from __future__ import unicode_literals
>>> import sys
>>> if sys.version_info < (3,):
...     text_type = unicode
...     binary_type = str
... else:
...     text_type = str
...     binary_type = bytes
>>> isinstance('U\xf1ic\xf6de', text_type)
True

[jmichelsen]

Sure. I'll update this