Better packaging & testing

## Packaging improvements:

* Include authors and changelog files.
* Add setup.cfg for binary distribution. To build, do this:

```bash
pip install "pip>=1.4" "setuptools>=0.9" "wheel>=0.21"
python setup.py sdist
python setup.py bdist_wheel
``` 

## Testing improvements:

* Add testing dependency on unittest2.
* Add Python 2.6 to Travis config.
* Clean up PEP8 and PyLint violations, add both to Travis builds.