appveyor: drop Python 3.4 to speed up CI builds
appveyor: drop Python 3.4 to speed up CI builds

We don't use Python 3 specific features, since our code has to be 2.7-compatible.
So there's no need to test different Python 3 versions. The current one is enough.

anthrotype/fontMath,moyogo/fontMath,typesupply/fontMath