Only #include <avr/dtostrf.h> for SAM/SAMD
Only #include <avr/dtostrf.h> for SAM/SAMD

#include <avr/dtostrf.h> is required for Due and Zero compatibility but
causes compile error on Arduino 101, Galileo, and Edison. Arduino 101
has its own implementation of dtostrf() but Galileo and Edison don't .

per1234/EtherEvent