Resolve CWG-11 "Features/ add tox"

Closes CWG-11

tox.ini

@@ -24,7 +24,7 @@ usedevelop = False
 envdir = {toxworkdir}/linting
 commands =
     pep8: {envpython} -m flake8 --version
-    pep8: {envpython} -m flake8
+    pep8: {envpython} -m flake8 --extend-exclude './.venv/','./venv/'
     black: {envpython} -m black --version
     black: {envpython} -m black --check --diff .
     pylint: {envpython} -m pylint --version