Backport PR #5478: Add git-hooks install script. Update README.md
Backport PR #5500: check for Python 3.2

in setup.py and init

treats unsupported 3.x < 3.3 like unsupported 2.x
Backport PR #5501: remove inappropriate wheel tag override

I misunderstood how these tags are interpreted. We do not want `py2` and `py3`, we want `py27` and `py33`, which indicate >= matching in the minor version.

This means we should build wheels with the minimum supported Python.