Python 3.3.1

Refactor project code to work with Python 3.3.1.

All tests pass with Python 3.3.1.
Merge branch 'dev/python3' into develop
Prepare release 0.3.0

Update version number.

Update changelog.

Update dependencies. 'iomanager>=0.4.0' required.

Add 'README_pypi.txt'. This is a brief readme for the 'pypi' project
page.
Merge branch 'release-0.3.0'