added callbacks
for all of the Z-Wave thermostat events
Next up: fill them in
filled in Z-Wave Thermostat callbacks
So now the ZWaveThermostat's state is updated whenever the ControlThink SDK says something happened.
Filing in the "Temperature Changed" callback meant removing the event code from the PollTemperature method.

TODO:
* Polling
* events
updated IThermostatState's Describe method
to show more state information.