Guidelines for contributing

1. Fork the repository.
2. Create a topic branch.
3. Make your changes, including tests for your changes.

4. Ensure that all tests pass, by running:

   composer install --dev
   cd tests && php all_tests.php && cd ..
   

   The Travis CI build runs on PHP 5.3 and 5.4.

5. It should go without saying, but do not increment the version number in your commits.

6. Submit a pull request.