Log Message:
py-sh: updated to 1.14.1

1.14.1:
* bugfix where setting `_ok_code` to not include 0, but 0 was the exit code

1.14.0:
* `_env` now more lenient in accepting dictionary-like objects
* `None` and `False` arguments now do not pass through to underlying command
* Implemented `find_spec` on the fancy importer, which fixes some Python3.4+