EmonPI firmware build

@pb66
Remember that about the time the “fix” was introduced, we asked JeeLabs to elucidate what they meant by

[you can] check whether a new RFM12B packet was received when you are ready for it. The simplest way is to add a call to rf12_recvDone() in the loop() body, and then simply make sure that the loop will be traversed “reasonably often”.

The purpose of rf12_recvDone() is explained:

The central RF12 driver check is the call:

    if (rf12_recvDone()) ...

From the caller’s perspective, its task is to find out whether a new packet has been received since the last call. From the RF12’s perspective, however, its task is to keep going and track which state the driver is currently in.

We never got an answer.