add validation of update responses at least once per update interval

[andrewhodel]

Only one update message is sent every update interval.

If there is network congestion, there is no retry until the next update interval and this could cause invalid outages.

[andrewhodel]

The sequence numbers are not needed because the order of updates is verified or never delivered to the server by the TCP sequence numbers that already exist. This means that there will never be an out of order update that is sent from the same TCP origin ONLY IF THE TCP SEQUENCE NUMBER IS ACCOUNTED FOR BY THE SERVER WITH UPDATE REQUESTS.

There needs to be a sequence number sent by the client and sent in the update response in update requests, not in config requests because the update requests send data that is charted through time.

[andrewhodel]

The sequence number from TCP is not available in Go.

If the client sends sequence numbers in the update JSON instead, the gain is knowing that client restarted.

The loss is that the client now must ensure resends because an initial message number of 0 after a client start or restart will require that 1 is never sent if the previous last sequence number sent was 1.

[andrewhodel]

The listener was upgraded to accept sequence numbers and validate them if they are sent in #8