distutils setup.py script
setup.py: Use setuptools instead of distutils

- distutils does not provide any usable dependency management
Add tox config and ignore .tox
Make it possible to run tests via setup.py and make tox do this
setup.py: List dependency on PyQt5 but make tox use global one

- It's commented out though because it can't be handled by setuptools automatically.
Ignore *.egg and *.egg-info