* Improve auto close implementation
- Register all envs at initialization time, not just ones created via make
- Simplify names and add more documentation on interface
- Move closer instances into the relevant modules
review-requested: @jietang
* Close environments in the tests
This isn't strictly needed, but means there are fewer Doom
subprocesses hanging around while the tests run.
* Use 4 space indent in comment
* Improve docstrings in core
* Don't pass through args to __new__
The __init__ method gets called once __new__ returns,
so these arguments are either ignored (Python 2) or
result in an error (Python 3). The __init__ method
automatically gets called with the correct arguments.
* Fixup comments
