Remove duplicate entry.
Add more Python versions.
Add check for alphabet length.
Switch from distutils to setuptools.
Enable wheel packages.

To build a wheel package:
python setup.py bdist_wheel
Add tests.
Add needed requirements and tox configuration.

To run the tests:
$ pip install -r requirements/devel.txt
$ tox
Merge pull request #2 from paetzke/master

Some improvements.

- Enabled wheel package
- Added tests and tox configuration
- Added check for alphabet length