Hartmut Goebel <h.goebel@crazy-compilers.com> [Tue, 17 Mar 2020 10:12:14 +0100] rev 41
Convert yml2 into a Python package.
* Rename yml2.py -> yml2/__init__.py
* Rename backend.py -> yml2/backend.py
* Rename pyPEG.py -> yml2/pyPEG.py
* Use relative imports where appropriate.
* Change imports in yml2c, yml2proc.
* Update make target `clean`.