add / fix unintuitive lower level multirotor APIs

[madratman]

add / fix unintuitive lower level APIs - RPYZ|Throttle, AngleRateZ|Throttle

Todos:

• mavlinkvehicleimpl.h/cpp, mavlinkvehicle.h/cpp. do we need to scale from throttle from [0,1] to [-1,1]
• Docs
• release new python client
• Enable on the fly gain tuning
• Incorporate Added moveByRotorSpeed command for QuadX #890 as moveByMotorPWMs

Should subsume #1984

[madratman]

Will add docs and example script in next PR.

[madratman]

To answer (the now deleted?) question by Pawel Jaworski - moveByMotorPWMs is documented here https://github.com/microsoft/AirSim/blob/master/PythonClient/airsim/client.py#L366-#L379

[aftersomemath]

The old "low level" API's moveByAngleZAsync and moveByAngleThrottleAsync are still present in the Python client. However, these functions no longer cause any movement of the simulated multirotor.

AirSim/PythonClient/airsim/client.py

Lines 337 to 340 in 1468615

	def moveByAngleZAsync(self, pitch, roll, z, yaw, duration, vehicle_name = ''):
	return self.client.call_async('moveByAngleZ', pitch, roll, z, yaw, duration, vehicle_name)
	def moveByAngleThrottleAsync(self, pitch, roll, throttle, yaw_rate, duration, vehicle_name = ''):

I am not sure what the desired resolution should be. Perhaps the old functions can wrap the new API calls and log deprecation warnings? My outer loop controller used for previous versions of AirSim broke silently when upgrading to the latest release and this took a little while to track down.

I am very excited that moveByMotorPWMs was implemented. I was planning to dig in and implement this myself, so this bug/discovery has saved me quite a bit of time. 👍