Have taken a few more steps towards support for view dependant transformations

by adding a ComputeTransformCallback to osg::Transform, and have now removed
the recently added AutoTransform since it is nolonger required.  Have also
updated CullVisitor to account for the new ways for tracking transformation
matrices in the scene.

include/osg/Node

@@ -27,7 +27,7 @@ class Group;
         virtual osg::Object* clone(const osg::CopyOp& copyop) const { return new name (*this,copyop); } \
         virtual bool isSameKindAs(const osg::Object* obj) const { return dynamic_cast<const name *>(obj)!=NULL; } \
         virtual const char* className() const { return #name; } \
-        virtual void accept(osg::NodeVisitor& nv) { if (nv.validNodeMask(*this)) nv.apply(*this); } \
+        virtual void accept(osg::NodeVisitor& nv) { if (nv.validNodeMask(*this)) { nv.pushOntoNodePath(this); nv.apply(*this); nv.popFromNodePath(); } } \
         
 
 /** Base class for all internal nodes in the scene graph.