Updated the README with the p3_safe API change.
Added .travis.yml for travis-ci.org.
Fixed doctests to make them pass on Python 3.2.
Moved unit-testing framework to pytest.

Previously, unit testing was done using doctests, but this quickly got
out of hand. All 'serious' unit tests have been moved to a proper unit
testing framework, but a few doctests remain for actual documentation
purposes.

By doing this, the public API docstrings were able to better mirror
the API presented in the README.

Test coverage is now 99%, so most exception paths are tested.  The
remaining 1% is an exception path that may not be possible to reach.
Added the versorted convenience function.

This function is a wrapper around 'natsorted(seq, number_type=None)',
and is provided because it appears that sorting version numbers is a
common task for the natsort package.
Added a reverse filter for the command-line tool.

This new command line tool allows the user to specify a range of numbers
they want to exclude from the results.
Natsort version 3.3.0 release.

This release provides the following updates:
    - Added a 'versorted' method for more convenient sorting of versions.
    - Updated command-line tool --number_type option with 'version' and
      'ver' to make it more clear how to sort version numbers.
    - Moved unit-testing mechanism from being docstring-based to actual
      unit tests in actual functions.
      - This has provided the ability determine the coverage of the unit
        tests (99%).
      - This also makes the pydoc documentation a bit more clear.
    - Made docstrings for public functions mirror the README API.
    - Connected natsort development to Travis-CI to help ensure quality
      releases.