Add a get_all_list_data utility function that uses a get_next generator ...

...function to retrieve all json data for methods that return a list and support pagination.  Include tests and function doc.
You're right about the "or" notation - I had started out returning a wrapped list [json_data] so the or wasn't an option then but I came back and removed the list to test for the case where something other than a list was returned.  I can change it when I'm back on Monday.  The "or" notation wouldn't handle an empty list, but I wouldn't pass that in to this test helper function anyway - I think I'll make the suggested change of "or" but otherwise leave it as is.