Changes

Into gzz.vob.VobCoorder add:

/** Creates a CullingCoordSys with distinct parent and test 
 * coordinate systems. Exluding the test for drawing, the 
 * CullingCoordSys works like its parent coordinate system.
 * E.g. CullingCoordSys returns its parents box. 
 *
 * This coordsys will not necessarily be drawn if the boxes
 * of the test and clip coordinate systems do not intersect.
 * However, this is not guaranteed; the only thing guaranteed
 * is that if the boxes of the test and clip coordinate systems
 * *do* intersect, the CullingCoordsys will be drawn.
 *
 * @param parent ID of the coordinate system which points 
 *               will be transformed, if CullingCoordSys 
 *               is shown
 * @param test ID of the coordinate system whose box is tested 
 *             against the clip coordinate system.
 * @param clip ID of the coordinate system whose box is tested
 *             against the test coordinate system.
 */
public int cull(int parent, int test, int clip) {
}

/** Creates a CullingCoordSys using the parent also as the test 
 * coordinate system. 
 */
public int cull(int parent, int clip) {
  cull(parent, parent, clip);
}