Integrated fixes to the detailed depth calculation in the CullVisitor from

Sasa, and fix to the IntersectVisitor's management of path from Sean.

src/osgUtil/IntersectVisitor.cpp

@@ -274,6 +274,7 @@ void IntersectVisitor::leaveNode()
 {
     IntersectState* cis = _intersectStateStack.back().get();
     cis->_segmentMaskStack.pop_back();
+    _nodePath.pop_back();
 }