public override void OnInspectorGUI()
 {
     aux = (ObjArray)target;
     GUILayout.BeginHorizontal();
     base.OnInspectorGUI();
     if (GUILayout.Button("Previous"))
     {
         aux.Ant();
     }
     if (GUILayout.Button("Next"))
     {
         aux.Prox();
     }
     GUILayout.EndHorizontal();
 }