General Updates
- Added tox to serve as the unit testing infrastructure, and changed which unit tests were run (see the github actions to see what exactly is running)
- Added tests to check future versions of numpy and astropy
- Added back in the remote data unit tests
xarray_to_cdf
- Added an ISTP check to determine is attribute and variable names are compliant
cdfwrite
- Clearer error message surrounding data type conversions to CDF data types