aggregate text of sub nodes aswell

ERP5Diff.py

@@ -348,7 +348,7 @@ class ERP5Diff:
     """
       Aggregate child text nodes of an element into a single string.
     """
-    return '%s' % element.xpath('string(text())')
+    return '%s' % element.xpath('string(.)')
 
   def _removeStrictEqualsSubNodeList(self, old_list, new_list):
     """Remove inside list all elements which are similar