* attitude and rate setpoint message: use 3D array for thrust demand
* FixedWingAttitudeControl: rework airspeed scaling
* move airspeed and scaling calculation into separate method
* if vtol in hover and airspeed disabled use minimum airspeed instead of trim airspeed
* added ability to slew rate limit the roll angle output of the l1 controller
* FixedWingPositionControl: this avoids the steps in roll angle setpoint which occur when the controller
switches to a new waypoint
* GroundRoverPositionControl: adapted to new l1 API
The TECS controller belongs really into the ECL (estimation & control library) where we have collected a number of vehicle control systems. It is being replaced by a new implementation of the algorithm, contributed by Paul Riseborough.