hml-validate: verbosity
hml-validate: Validate -> Validator
hml-validate: exact match for higgsm-xyz scripts
hml-validate: better help message
hml-validate: handle directory-or-archive
hml-validate: add copytree
hml-validate: higgsml_simplest_v2.py -> higgsml-simplest.py
py: make python-2/python-3 compatible
py: better py2-py3 bwf/fwd compat
py: (even) better py2/py3 bwf/fwd compat
test: use python. not python2.