v0.0.19 (#50)

To pick up #49.

Merge pull request #48 from heroku-python/python3

Cleanup for Python 3 compat

Merge pull request #46 from heroku-python/allow-no-override

update so override_path checks for None

Merge pull request #45 from heroku-python/bugfix-release

update version for new release

update setup.py version to cut new release (#41)

update author to Heroku