Major overhaul:

- transition to `pyproject.toml` config
- include license (Apache-2.0)
- add dev tools
- add documentation config (`mkdocs` based)
- turn `README.md` into a symlink to docs `index.md`
- add convenience scripts for testing and linting

tests/__main__.py

@@ -0,0 +1,13 @@
+import sys
+import unittest
+
+
+if __name__ == "__main__":
+    try:
+        pattern = sys.argv[1]
+    except IndexError:
+        pattern = "test*.py"
+    test_suite = unittest.defaultTestLoader.discover(".", pattern=pattern)
+    test_runner = unittest.TextTestRunner(resultclass=unittest.TextTestResult)
+    result = test_runner.run(test_suite)
+    sys.exit(not result.wasSuccessful())