Upgrade virtualenv and tox on appveyor
Upgrade virtualenv and tox on appveyor

michaeljoseph/cookiecutter,hackebrot/cookiecutter,audreyr/cookiecutter,audreyr/cookiecutter,michaeljoseph/cookiecutter,pjbull/cookiecutter,luzfcb/cookiecutter,pjbull/cookiecutter,hackebrot/cookiecutter,luzfcb/cookiecutter