FIX: Parse commas in CSV fields

[zachlindsey]

Summary

Fixes #3635

List of changes proposed in this PR (pull-request)

• Use the csv library to parse CSV files, so that quoted fields are correctly parsed.
• Add a delimiter field to CSVReader so that things like TSVs can be parsed.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 63.14%. Comparing base (c46a957) to head (5e84919).
Report is 7 commits behind head on master.

❗ Current head 5e84919 differs from pull request most recent head f746c34. Consider uploading reports for the commit f746c34 to get more accurate results

Additional details and impacted files

@@ Coverage Diff @@ ## master #3637 +/- ## ========================================== - Coverage 63.15% 63.14% -0.01%  ========================================== Files 308 308 Lines 40825 40824 -1 Branches 5656 5655 -1 ========================================== - Hits 25781 25780 -1  Misses 14031 14031 Partials 1013 1013 

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[effigies]

LGTM. Small cleanup to avoid escaping quotes.