add robotics learning grasp contact example

add wsg50 gripper with modified r2d2 gripper tip
expose a fudge factor to scale inertia, to make grasping more stable
(until we have better grasping contact model/implementation)

examples/ExampleBrowser/OpenGLExampleBrowser.cpp

@@ -519,6 +519,8 @@ void MyStatusBarError(const char* msg)
 		gui2->textOutput(msg);
 		gui2->forceUpdateScrollBars();
 	}
+    btAssert(0);
+
 }
 
 struct MyMenuItemHander :public Gwen::Event::Handler