Put the ordering of the callbacks so that the update callback is first,

then cull then draw.  Added missing copy of update callback into copy
constructor.

include/osg/Drawable

@@ -692,8 +692,8 @@ class SG_EXPORT Drawable : public Object
         mutable GLObjectList    _vboList;
 
         ref_ptr<UpdateCallback> _updateCallback;
-        ref_ptr<DrawCallback>   _drawCallback;
         ref_ptr<CullCallback>   _cullCallback;
+        ref_ptr<DrawCallback>   _drawCallback;
         
 
 };

src/osg/Drawable.cpp

@@ -154,8 +154,9 @@ Drawable::Drawable(const Drawable& drawable,const CopyOp& copyop):
     _useDisplayList(drawable._useDisplayList),
     _supportsVertexBufferObjects(drawable._supportsVertexBufferObjects),
     _useVertexBufferObjects(drawable._useVertexBufferObjects),
-    _drawCallback(drawable._drawCallback),
-    _cullCallback(drawable._cullCallback)
+    _updateCallback(drawable._updateCallback),
+    _cullCallback(drawable._cullCallback),
+    _drawCallback(drawable._drawCallback)
 {
 }