plumb URDF/SDF audio_source into PhysicsServerCommandProcessor, allow to play sounds on collision !

See also https://youtu.be/eppOjTfx5Jg for a first test, and this modified URDF how to add sounds:
https://github.com/bulletphysics/bullet3/blob/master/data/plane_with_collision_audio.urdf
Add the --audio flag to enable sound in pybullet/Bullet-C-API

examples/TinyAudio/b3SoundSource.h

@@ -24,7 +24,7 @@ public:
 
 	bool setWavFile(int oscillatorIndex, class b3ReadWavFile* wavFilePtr, int sampleRate);
 
-	void startSound();
+	void startSound(bool autoKeyOff);
 	void stopSound();
 
 	bool isAvailable() const;