- _Backwards-incompatible_: Remove `stream` argument from `read_env`,
since it had no effect ([114](https://github.com/sloria/environs/pull/114)).
- _Backwards-incompatible_: `Env.read_env` consistently returns `None`
([111](https://github.com/sloria/environs/pull/111)).
- Remove unnecessary `__str__` definition ([112](https://github.com/sloria/environs/pull/112)).
Thanks [hukkinj1](https://github.com/hukkinj1) for the PRs.