Allow slightly more latitude in what is passed as the children array

common/lib/xmodule/x_module.py

@@ -76,7 +76,7 @@ class XModule(object):
         location: Something Location-like that identifies this xmodule
         definition: A dictionary containing 'data' and 'children'. Both are optional
             'data': is JSON-like (string, dictionary, list, bool, or None, optionally nested)
-            'children': is a list of xmodule urls for child modules that this module depends on
+            'children': is a list of Location-like values for child modules that this module depends on
         instance_state: A string of serialized json that contains the state of this module for
             current student accessing the system, or None if no state has been saved
         shared_state: A string of serialized json that contains the state that is shared between