Python 3 support

[betodealmeida]

Python 3 support using the six module is in progress. Finish the port for release 3.2.1.

[PaulSorenson]

I noticed the sphinx docs fail in python3.4 on source I cloned from the repo today. It was only after fixing them I came here. Since I didn't use six my changes probably aren't appropriate to merge. I could possibly have a look at doing this with six if nobody else is - any advice you guys have?

[shoyer]

@PaulSorenson in my experience, six really isn't necessary for mixed Python 2/3 support these days. So I would say it's fine not to use it.

[lewismc]

This issue is addressed right? @jameshiebert

[jameshiebert]

Indeed it is.