Dronekit

Improvements
* CI integration improvements
* Python3 compatability
* use logging module
* log statustexts
* documentation improvements
* convenience functions added: wait_for, wait_for_armable, arm, disarm, wait_for_mode, wait_for_alt, wait_simple_takeoff
* play_tune method added
* reboot method added
* send_calibrate_gyro, send_calibrate_magnetometer, send_calibrate_magnetometer, send_calibrate_vehicle_level, send_calibrate_barometer all added
* update gimbal orientation from MOUNT_ORIENTATION
* add a still-waiting callback for connect() to provide debug on where the connection is up to
* several new tests added (including, play_tune, reboot and set_attitude_target)

Cleanup
* flake8 compliance improvements
* test includes pruned
* examples cleaned up

Bug Fixes
* ignore GCS heartbeats for the purposes of link up
* many!

Improvements
* home locatin notifications
* notify ci status to gitter
* basic python 3 support
* isolated logger function so implementers can override
* rename windows installer

Cleanup
* removed legacy cloud integrations

Bug Fixes
* fix missing ** operator for pymavlink compatibility

Bug Fixes
* MAVConnection stops threads on exit and close
* PX4 Pro flight modes are now properly supported
* go to test now uses correct `global_relative_frame` alt

Improvements
* Updated pymavlink dependency to v2 from v1 hoping we don't fall behind
again.

Bug Fixes
* Makes sure we are listening to `HOME_LOCATION` message, befor we
would only set home location if received by waypoints.

Improvements
* Adds udpin-multi support

Bug Fixes
* Fixes patched mavutil sendfn