3.3.0 release

New version (3.2.1) to correct an uncommited test in Pypi package

Update CHANGELOG and setup for 3.2.0

Merge pull request #12 from mckaymatt/add-BooleanOptionalAction-action

Add builtin BooleanOptionalAction Action

README update for PyPi

Set version to 2.3.1.

Set version to 2.3.0.

Set release version to 2.2.0 and update README.

Set release version to 2.1.1 and update README.

Set release date in README.