def exploded_namespace_declarations(ns)
      Hash[ns.map do |prefix, uri|
             if prefix==""
               ["xmlns", uri]
             else
               [[prefix, "xmlns"], uri]
             end
           end]
    end
def exploded_namespace_declarations(ns)
      Hash[ns.map do |prefix, uri|
             if prefix==""
               ["xmlns", uri]
             else
               [[prefix, "xmlns"], uri]
             end
           end]
    end
produce a Hash of namespace declaration attributes with exploded
 QNames, from
 a Hash of namespace prefix bindings