fix logical error in generating/sending packets

There was a bug in the workflow of generating & sending packets, if MeasuringInterval & AveringInterval of 2 sensors are all set to 1, to send a value every time the device wakes up by timer. Only the first value is sent, the other is collected forever.
Sending the packet moved to a subroutine, gets called for every value which has reached the counter. Switch the LED on while the encrypted packet is sent to the RFM12B buffer, no need to wait every time.