Fix typo in README.
Fix requirements in setup.py.

`argparse` is nw in Python 2.7 resp. 3.2, soe we need to require it
in case one uses 2.6 (which is the minimum version required by
Ansible).
Update trove classifiers.
Merge pull request #68 from htgoebel/master

Some minor fixes for preparing the release at PyPI.