fix: pkg: generated ``setup.py`` do not support file names on the same line, this prevented installation via ``pip install``.
chg: pkg: removed spurious trailing whitespaces. @minor
new: pkg: generate the ``setup.py`` files from ``setup.cfg`` so that PyPI packages are compatible with ``setuptools``-like installers (as ``pip``).
fix: doc: forgot to mention ``./autogen.sh`` execution when getting the code from git, and be more clear about other means of installation.