Device status message improvements, timer stop, and other minor tweaks.

Stan,
This pull represents some significant improvements to the status message and event reliability. It seems that the device type responds better when event replies are sent outside of the loop that processed the incoming messages. Also, seems like you had the PIN sets reversed. I needed to set them HIGH to close the relay and LOW to open the relay. I think that is what you were going for. That way, when the relays are wires on the NO pins, a current is required to close the circuit (and turn the valve on). Power loss to the Arduino will open all relays (shutting off all valves). Perhaps your relay board works different than mine, but I think this is the normal behavior.

Thanks for this code. I now have very smart Smart Sprinklers. :)