-- the accessed method will now fail outside of the persistence manager (as
   it should have been doing all along)
-- the accessed method will try to access the persistence manager if it can
   to try and lazy load a xampl object

-- replaced s.to_s with s.dup.to_s in content_esc and attribute_esc in
   to_xml and pp_xml, because s.to_s returns itself when it is a string
   and this caused the escaping to change the original string.

-- fixed the ensure* method for non-indexed children (no longer aliased with
   new* so no longer does this create a new child each time it is called)

-- ATTENTAION: if you are accessing attributes directly in an opened xampl class
   then DO NOT FAIL to call accessed