Add Python 3 trove classifier to setup.py so that Python 3 wall of shame...

I don't have any Windows VM anymore, so I didn't run the tests there. But the diff looks good and the tests continue to pass on my Mac. So I'll merge this as-is.

should pass a full environment. The rest of the buildout code already
does this.

3.3

option, -Wno-unused-result, which appears no where in buildout or
distribute code.  Ignore it.

Python 3.3, so we have to normalize data when computing package
hashes.

Sort dict-based data for consistent output.

removed failed attempt at isolation via -S

Support multiple Pythons in the same working tree