Add python 3.7 to appveyor and remove unneeded setup steps
Add python 3.7 to appveyor and remove unneeded setup steps

BruceSherwood/vpython-jupyter,BruceSherwood/vpython-jupyter,BruceSherwood/vpython-jupyter,BruceSherwood/vpython-jupyter,mwcraig/vpython-jupyter,mwcraig/vpython-jupyter,mwcraig/vpython-jupyter,mwcraig/vpython-jupyter