remove some warnings

src/BulletDynamics/Featherstone/btMultiBody.cpp

@@ -2329,7 +2329,6 @@ void	btMultiBody::forwardKinematics(btAlignedObjectArray<btQuaternion>& world_to
 	
 	for (int i = 0; i < num_links; ++i) 
 	{
-		const int parent = m_links[i].m_parent;
 		rot_from_parent[i+1] = btMatrix3x3(m_links[i].m_cachedRotParentToThis);
 	}
 		

src/BulletDynamics/Featherstone/btMultiBodyConstraintSolver.cpp

@@ -895,7 +895,6 @@ void btMultiBodyConstraintSolver::writeBackSolverBodyToMultiBody(btMultiBodySolv
 
 	if (c.m_multiBodyA)
 	{
-		btScalar ai = c.m_appliedImpulse;
 		
 		if(c.m_multiBodyA->isMultiDof())
 		{

src/BulletDynamics/Featherstone/btMultiBodyDynamicsWorld.cpp

@@ -838,11 +838,9 @@ void	btMultiBodyDynamicsWorld::debugDrawWorld()
 				
 				getDebugDrawer()->drawTransform(bod->getBaseWorldTransform(), 0.1);
 
-				int nLinks = bod->getNumLinks();
 
 				for (int m = 0; m<bod->getNumLinks(); m++)
 				{
-					int link = m;
 					
 					const btTransform& tr = bod->getLink(m).m_cachedWorldTransform;
 

src/BulletDynamics/Featherstone/btMultiBodyJointMotor.cpp

@@ -26,7 +26,6 @@ btMultiBodyJointMotor::btMultiBodyJointMotor(btMultiBody* body, int link, btScal
 	m_desiredVelocity(desiredVelocity)
 {
 
-	int parent = body->getLink(link).m_parent;
 	m_maxAppliedImpulse = maxMotorImpulse;
 	// the data.m_jacobians never change, so may as well
     // initialize them here