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

fixed dev.py on windows

This way you can run the tests against several python versions by doing

  make PYTHON_VER=2.6 build test
  make PYTHON_VER=2.7 build test
  make PYTHON_VER=3.2 build test

repeatedly, without having to re-download and recompile the respective
clean Python interpreters.

removing debugger, adding comments

Fix nondeterministic buildout.txt test failure

If the test happened to write to mkdir.py twice in the same second,
Python's import cache wouldn't notice that the .pyc file is stale and
would execute old code.