DatasetGraphMonitor exposes unwrapped graphs

   public class TestDatasetMonitor extends BaseTest {
    ...
    @Test public void countChanges_05() {
        DatasetGraph dsgBase = DatasetGraphFactory.create() ;
        DatasetChangesCounter dsgChanges = new DatasetChangesCounter() ;
        DatasetGraph dsg = new DatasetGraphMonitor(dsgBase, dsgChanges) ;

        check(dsgChanges, 0, 0, 0, 0) ;
        Graph g = dsg.getDefaultGraph();
        g.add(quad1.asTriple()) ;
        g.delete(quad1.asTriple()) ;
        g.add(quad1.asTriple()) ;
        g.delete(quad1.asTriple()) ;
        check(dsgChanges, 2, 2, 0, 0) ; 
    }