remove suppor for Python <= 3.3

[a-detiste]

No description provided.

[wswld]

Hi @a-detiste what is the reason for this change?

[a-detiste]

Hi, I've been proposing hundreds of those patches while reviewing/removing "Dead Batteries" from Debian.
https://wiki.debian.org/Python/Dead%20Batteries

I don't have any hard, irrefutable arguments; I didn't checked your project thoroughtly to proove it possibly already broke Py2.x compatibility in some ways. (I didt for others that were in a messy state) I still have the same feelling that keeping Py2.x comaptibility nowadays is hindereing project from evolving.

https://wiki.debian.org/Python3-six-removal

[a-detiste]

But well it's the case here too:

b7cfa04#diff-55bc76c984a09eef37a3a2116dd6187416f3f3910f4fc2113f36d5ae2b2e2ba6L23

[a-detiste]

Python 3.0 / 3.1 / 3.2 had (almost) no external library ported and very little real-life users.