Add license file
Prepare PyPI packaging

- Remove requirements.txt file, since this is a library we'll use
  install_requires in setup.py instead. Leave requirements-dev.txt
  though, as only devs need to install this.

- New setup.py and setup.cfg. Includes new version number 0.0.1,
  description, classifiers etc.

- New MANIFEST.in file to include README.md in package
Edit the README