Mod. changed pkl_data to Autovivification type.
Mod. changed pkl_data to OrderdDict type.  Added methods to retrieve and add data to the global hash.
Mod. get_agg_key() method to handle instances where non-string handle representation are passed.
Mod. interface to process_data_request() and handling of aggregator handle.
Mod. remove references to url in process_metrics.  Requests are now primarily decoupled from urls.