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

scripts/lint.sh

@@ -0,0 +1,16 @@
+#!/usr/bin/env bash
+# Runs type checker and linters.
+
+# Ensure that we return to the current working directory
+# and exit the script immediately in case of an error:
+trap "cd $(realpath ${PWD}); exit 1" ERR
+# Change into project root directory:
+cd "$(dirname $(dirname $(realpath $0)))"
+
+echo 'Performing type checks...'
+mypy
+echo
+
+echo 'Linting source and test files...'
+flake8 src/ tests/
+echo -e 'No issues found.'