Update extensions to prefer to use ns_alias as name
diff --git a/flask_openid.py b/flask_openid.py
index cf648d9..aef0dde 100644
--- a/flask_openid.py
+++ b/flask_openid.py
@@ -149,7 +149,8 @@
         # Process the OpenID response with the OpenIDResponse class provided
         self.ext = {}
         for extension in extensions:
-            self.ext[extension.__name__] = \
+            ext_name = getattr(extension, 'ns_alias', extension.__name__)
+            self.ext[ext_name] = \
                 extension.fromSuccessResponse(resp)
 
     def get(self, name, default=None):