Issue #113, split json_response into two functions 

json_response_string creates a response from a string message and json_response_dict creates a response from a dictionary of data. The function calls to json_response in auth.py have been changed to json_response_string and json_response_dict.
These should be renamed `json_response_from_message` and `json_response_from_dict`, and then you shouldn't need to import `json_response` (because it will be deprecated).`