Add valid data flag

[borpin]

I have found the temperature sensor to be a little unreliable.

I propose always returning a response and adding a data_valid item to the returned message.

This only covers the case where data is actually being sent. As there are a number of other occasions where data is not returned, where an error or a warn should be raised. A second output with a status code could be used.

BTW this is a great node!

Cheers

[eschava]

Sorry, but I think "Status" node does the same work

[borpin]

Fair enough.