Convert to reStructuredText.
Move tests folder to toplevel and apply PEP8 to tests.
Refactor setup.py.

- Add __meta__.py file for project data.
- Use tox, twine, and wheel.
- Add test requirements to main requirements file.
- Expand makefile targets with various build, test, and distribution
targets.
PEP8.
Fix typo.
Update changelog for v0.5.0.
Remove unnecessary parent class.
Release v0.5.0.