* tree.c include/libxml/tree.h: Fixed a bug in
  xmlDOMWrapAdoptNode(); the tree traversal stopped if the
  very first given node had an attribute node :-( This was due
  to a missed check in the traversal mechanism.
  Expanded the xmlDOMWrapCtxt: it now holds the namespace map
  used in xmlDOMWrapAdoptNode() and xmlDOMWrapCloneNode() for
  reusal; so the map-items don't need to be created for every
  cloning/adoption. Added a callback function to it for
  retrieval of xmlNsPtr to be set on node->ns; this is needed
  for my custom handling of ns-references in my DOM wrapper.
  Substituted code which created the XML namespace decl on
  the doc for a call to xmlTreeEnsureXMLDecl(). Removed
  those nastly "warnigns" from the docs of the clone/adopt
  functions; they work fine on my side.