* Add `--python` option for `nbstripout --install` to allow overriding the Python interpreter specified in `.git/config` (nobodyinperson, 181, 182)
* Add option `--keep-metadata-keys` to keep specific metadata keys that are stripped by default (davidxia, 177, 78)
* Replace [Cram](https://bitheap.org/cram/) as test runner for integration tests with a custom framework which also supports testing on Windows (arobrien, #176, 178)
* Use `SystemExit` instead of `sys.exit` and do not exit from functions (janosh, 173)