Add pytest.ini that adds py.test options

Esepcially:

    --assert=reinterp

which prevents the following:

      File
    "/Users/marca/dev/git-repos/capturemock_examples/.tox/py26/lib/python2.6/site-packages/_pytest/assertion/__init__.py",
    line 64, in pytest_unconfigure
        sys.meta_path.remove(hook)
    ValueError: list.remove(x): x not in list
test_requests.py: Make into a real py.test test
Add tox.ini and setup.py