CoinVisualizationFactory::renderOffscreenAndGetFocalLength now renders and returns the used focal length
CoinVisualizationFactory::renderOffscreen does not take a focal length parameter (coin3d does not use it)

the example CameraView does not show depth voxels anymore (they were wrong anyway)

Conflicts:
	VirtualRobot/Nodes/RobotNode.h

added some helper methods
improved performance of joint updates

render offscreen now takes custom values for zNear, zFar and the focal length

Results in much better IK behavior.

SceneObject::Physics: update the ::isSet() method to report true if the simulationType is not eUnknown

this fixes serialization of static Manipulation objects

Switched default behavior: use internal qhull version, since there are issues with newer versions that might be installed on the system