show.iqrdf in iqvoc-4.4.0

- old
+ new

@@ -1,5 +1,6 @@
-Iqvoc.default_rdf_namespace_helper_methods.each do |meth|
-  document.namespaces(self.send(meth))
+RdfNamespacesHelper.instance_methods.each do |meth|
+  namespaces = send(meth)
+  document.namespaces(namespaces) if namespaces.is_a?(Hash)
 end
 
 render_concept(document, @concept)