[Bug #713] Fix bug

The end date for task groups was not always being calculated. Now when
it is a parent recalculation the end is always calculated, this
ensures that the container has initially the right size since the
parent recalculation is always done.

FEA: ItEr63S03BugFixing

ganttzk/src/main/java/org/zkoss/ganttz/data/GanttDiagramGraph.java

@@ -1022,7 +1022,7 @@ public class GanttDiagramGraph<V, D extends IDependency<V>> implements
         private boolean enforceStartAndEnd(V task) {
             Set<D> incoming = graph.incomingEdgesOf(task);
             boolean startDateChanged = enforceStartDate(task, incoming);
-            if (startDateChanged) {
+            if (startDateChanged || parentRecalculation) {
                 enforceEndDate(task, incoming);
             }
             return startDateChanged;