Fix import of non-gwpy data + more unit tests -- partially addresses issue #47
- addressing issues from MDC about import of local files
- more unit tests
- fixing black -- it wasn't running at all previously, and probs people had different versions that would black things slightly differently and cause precommit failures. I now fixed it to be the current igwn-py38/py39 black=21.5b2
Edited by Arianna Renzini