core (xml_tools): fixed findAll

- names and namespases arguments haven been inverted to be in the same order as for domish.Element.elements
    - fixed bad copy of elements in recursions
    - check if childrens are IElements
    - namespaces and names can now be basestrings instead of iterables

src/plugins/plugin_blog_import.py

@@ -282,7 +282,7 @@ class BlogImportPlugin(object):
         tmp_dir = tempfile.mkdtemp()
         try:
             # TODO: would be nice to also update the hyperlinks to these images, e.g. when you have <a href="{url}"><img src="{url}"></a>
-            for img_elt in xml_tools.findAll(top_elt, ['img']):
+            for img_elt in xml_tools.findAll(top_elt, names=[u'img']):
                 yield self.imgFilters(client, img_elt, options, opt_host, tmp_dir)
         finally:
             os.rmdir(tmp_dir) # XXX: tmp_dir should be empty, or something went wrong