#3 Improve frequency of send commands to devices

[Mark Kendall]

Don't send commands to the device as frequently as is currently happening, try to be a bit more intelligent about it.
For example, if nothing has changed (ie the desired relay states) from the computer end possibly send once per minute, even less frequently if relays were turned off (and this was acknowledged)

This should be user configurable so that a user can decide to refresh every XXXX seconds, defaulting to something like every minute?