xarray for roti

[JonathonMSmith]

Description

Addresses #92

Added xarray loading of CDF files to cdaweb.py using the cdflib cdf_to_xarray function.

Type of change

• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

How Has This Been Tested?

Data has been loaded and compared to the CDAWEB viewer as well as the local unit tests.

Test Configuration

• Operating system: OSX
• Version number: [Python 3.9]
• Conda 4.10 environment.

Checklist:

• [sorta] Make sure you are merging into the develop (not main) branch
• [X] My code follows the style guidelines of this project
• [X] I have performed a self-review of my own code
• [X] I have commented my code, particularly in hard-to-understand areas
• [ ] I have made corresponding changes to the documentation
• [ ] My changes generate no new warnings
• [ ] I have added tests that prove my fix is effective or that my feature works
• [X] New and existing unit tests pass locally with my changes
• [] Any dependent changes have been merged and published in downstream modules
• [ ] Add a note to CHANGELOG.md, summarizing the changes
• [ ] Update zenodo.json file for new code contributors

[JonathonMSmith]

Forgot that this has been developed around the load_meta_proc branch from pysat. Happy to close this if it's inappropriate.

[jklenzing]

I say we keep developing this here and rely on local tests for the merge into the other PR. We can flag that one as waiting for next pysat.

[jklenzing]

This works locally with the latest pysat release. Can't re-run here, needs a commit to trigger this. You could merge in the latest develop changes if needed, but I think it's already downstream of the bug fixes.