* Problem: Source files contain no license info
Solution: Add comments with SPDX license info to source files
* Python 3 files don't need # -*- coding: utf-8 -*-
* Problem: acceptance-test suite is not documented
Solution: add README.md in the root of the acceptance tests, unify
`Makefile` and commands, remove more cached files when `make clean` is
ran.
* Problem: documentation does not mention Makefile
Solution: update docs with our new and shiny commands