VR video recording, use command-line --mp4=videoname.mp4

tune gripper grasp example with tefal pan, 800Newton force.
URDF importer: if using single transform 1 child shape, don't use compound shape.
if renderGUI is false, don't intercept mouse clicks
add manyspheres.py example (performance is pretty bad, will look into it)
[pybullet] expose contactBreakingThreshold

examples/CommonInterfaces/CommonExampleInterface.h

@@ -37,6 +37,7 @@ public:
 	
 	virtual void    initPhysics()=0;
 	virtual void    exitPhysics()=0;
+	virtual void	updateGraphics(){}
 	virtual void	stepSimulation(float deltaTime)=0;
 	virtual void	renderScene()=0;
 	virtual void	physicsDebugDraw(int debugFlags)=0;//for now we reuse the flags in Bullet/src/LinearMath/btIDebugDraw.h