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* switch test to pytest
* Use jinja_base for debug printing template files
* Add Environment customization for kwargs, filters, tests, globals, and policies
* Refactor debug printing and fix urllib import
* Use debug in tests - currently breaks on 3.7+
* Add CI environments for 3.6, 3.7, 3.8, 3.9, and 3.10
* Add requirements to requirements.txt and setup.py
* Add MIT license file
* README.rst: add debug option
* README.rst: fix formatting