feat: full upgrade to python3, tests, etc.

Makefile

@@ -0,0 +1,19 @@
+.PHONY: install format lint test check clean
+
+install:
+	@pip install -r requirements.txt
+
+format:
+	@ruff format .
+
+lint:
+	@ruff check .
+
+test:
+	@pytest --cov=aeonview --cov-report=term-missing
+
+check: lint test
+
+clean:
+	@find . -type d -name '__pycache__' -exec rm -r {} +
+	@rm -rf .pytest_cache .coverage htmlcov