Fix (needs more testing) in btRigidBody::setCenterOfMassTransform, assign m_interpolationWorldTransform = xform; instead of m_worldTransform;

Thanks Jay for reporting
Added braking capability to btRaycastVehicle, see Bullet/Demos/VehicleDemo/VehicleDemo.cpp
Added glutKeyboardUpFunc, for vehicle demo (keep accelerating/breaking, until key released/UP). Hope this is compatible with most GLUT implementations.

Demos/OpenGL/DemoApplication.cpp

@@ -368,6 +368,13 @@ void DemoApplication::keyboardCallback(unsigned char key, int x, int y)
 
 }
 	
+void DemoApplication::specialKeyboardUp(int key, int x, int y)
+{
+
+		glutPostRedisplay();
+
+}
+
 void DemoApplication::specialKeyboard(int key, int x, int y)	
 {
 	(void)x;