Add video background support

Mission editor (WIP)

- Restructured a number of MissionItem properties as well

appveyor support (windows ci)

fix linux unittests failure

Restructure map controls for better reusability

Conflicts:
	src/FlightDisplay/FlightDisplayView.qml

Don't show vehicle till 2d gps lock

Use true list models for vehicles and mission items

Fix UT only shutdown ordering crash

Allow custom firmware flash on PX4Flow

Decreasing the angle jitter threshold for row, pitch and yaw.

travis-ci fixes

Joystick message fixes

When on Joystick config page:
- Not calibrating: If joystick is enabled, joystick messages should
continue to go to vehicle

Joystick fixes