Fix the crashing issue when closing Blocks3d

Physics engine now destroys JointsService on destructor

src/source/XplicitNgine/XplicitNgine.cpp

@@ -20,6 +20,7 @@ XplicitNgine::XplicitNgine()
 
 XplicitNgine::~XplicitNgine() 
 {
+	g_dataModel->getJointsService()->remove();
 	dJointGroupDestroy (contactgroup);
 	dSpaceDestroy (physSpace);
 	dWorldDestroy (physWorld);