Add encrypted packet performance object to proto_docsis.
Add performance object to count NULL packets which are discarded.
Add read_queries and write_queries performances to datastores.
Add support for registry_perf update_hook.
Add perf objects for signal, snr, ber, uncorrected blocks for input_dvb.
Don't try to update the values if the input is not started.
Add support for registry class performance objects.
Add performance objects pkt_queue and active_thread for core class.