circle.yml: use latest available Python versions
circle.yml: use latest available Python versions

https://circleci.com/docs/1.0/build-image-trusty/#python
diydrones/dronekit-python,hamishwillee/dronekit-python,hamishwillee/dronekit-python,dronekit/dronekit-python,diydrones/dronekit-python,dronekit/dronekit-python