Delete a few names we import that are not intended for the user
Delete a few names we import that are not intended for the user

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