Add flake8 Config in Tox

This patch adds a config section for flake8 to tox and also add an ignore for
long lines, since it seems like these errors are already actively ignored.

Some IDEs (tested only vscode) will pick this up and make working a lot easier
and clearer.

Author: shaardie

tox.ini

@@ -17,3 +17,6 @@ commands =
   pip --version
   pip freeze
   pytest -vvv -ra {posargs:tests/}
+
+[flake8]
+ignore = E501