circle.yml: fix the build
circle.yml: fix the build

- Install future beforehand as workaround to pymavlink bug: https://github.com/ArduPilot/pymavlink/issues/25
- Install dependencies before dronekit, not after
hamishwillee/dronekit-python,diydrones/dronekit-python,diydrones/dronekit-python,dronekit/dronekit-python,dronekit/dronekit-python,hamishwillee/dronekit-python