Added osg::CullSettings class as a way of collecting all the various

settings related to the cull traversal in one place, so we can keep APIs
for settings these values more consistent.

examples/osgviewer/osgviewer.cpp

@@ -12,6 +12,7 @@
 #include <osgDB/ReadFile>
 #include <osgUtil/Optimizer>
 #include <osgProducer/Viewer>
+#include <osg/CoordinateSystemNode>
 
 int main( int argc, char **argv )
 {
@@ -84,10 +85,23 @@ int main( int argc, char **argv )
     osgUtil::Optimizer optimizer;
     optimizer.optimize(loadedModel.get());
 
+#if 0
+    osg::CoordinateSystemNode* csn = new osg::CoordinateSystemNode;
+    csn->addChild(loadedModel.get());
+    csn->setEllipsoidModel(new osg::EllipsoidModel());    
+
+    osg::NodePath nodepath;
+    nodepath.push_back(csn);
+    
+    viewer.setCoordindateSystemNodePath(nodepath);
 
     // set the scene to render
+    viewer.setSceneData(csn);
+#else
+
     viewer.setSceneData(loadedModel.get());
 
+#endif
     // create the windows and run the threads.
     viewer.realize();