Continued code cleanup
Added new tests for spectrum, bunch and mspectrum, contributed by svaberg
The release is also available on [PyPI](https://pypi.org/project/ChiantiPy/)
Documentation is available on [github.io](https://chianti-atomic.github.io/)
and on [ReadTheDocs](https://chiantipy.readthedocs.io/en/latest/?badge=latest)