Rewrote osg:Statistics so that it is PrimitiveFunctor as is now completely

decoupled from osg::Drawable.  The Drawable::getStats() virtual method
no longer exists.

Updated the Viewer to use the osg::Statistics incarnation and reformated stats
to clean it up.

src/osgUtil/IntersectVisitor.cpp

@@ -493,7 +493,7 @@ void IntersectVisitor::apply(Geode& geode)
 {
     if (!enterNode(geode)) return;
 
-    for(int i = 0; i < geode.getNumDrawables(); i++ )
+    for(unsigned int i = 0; i < geode.getNumDrawables(); i++ )
     {
         intersect(*geode.getDrawable(i));
     }