Assess handle updater for multiple nodes

[thclark]

Bug Report

In PacketReader.parse_packet(), we have a call (which originated in Raphael's old script) which allows the hardware to update its handles by sending a packet:

                        if packet_type == str(self.config.type_handle_def):
                            self.update_handles(packet)
                            continue

In moving to v3 (i.e. #64), this would become

packet_type == str(self.config.nodes[node_id].type_handle_def)

ie the different nodes could update handles differently.

However, we don't yet treat the handles as being different for each node; this could result in one node issuing an update that then corrupts data received from other nodes.

Workaround for implementing #64

We'll assume that the handles are consistent for each node and not worry about it for now, I'll close the loop with @tommasopolonelli to determine how this should be handled in future.

[thclark]

I've now implemented this during the solution to #64 - simpler than thought, so I'm closing.