Disable 'm_robotSim.setNumSimulationSubSteps' because it is not needed at the moment

Fix issue in contact/friction between btMultibody and btRigidBody (external force/torque of btRigidBody was not taken into account during contact/friction setup)
Allow 0.1 mm slop in contact, to avoid loosing contact. Todo: allow contacts with positive distance in multibody solver.

examples/RoboticsLearning/GripperGraspExample.cpp

@@ -152,7 +152,7 @@ public:
                 
             }
             m_robotSim.setGravity(b3MakeVector3(0,0,-10));
-            m_robotSim.setNumSimulationSubSteps(4);
+            //m_robotSim.setNumSimulationSubSteps(4);
         }