Major update. More boards supported

All supported platforms have been integrated into same source code for better maintenability. This opens the possibility to improve sync mechanism to get higher precission.

Some parts of library interface have been changed. Although I've tried to mantain backwards compatibility you may find any discrepancy with former versions. If so, let me know. You don't need to change your existing code to use this version.

Now, library is compatible with Arduino with Ethernet shield, ESP8266, MKR1000 and ESP32. It should be compatible with WiFi shield for Arduino too, although I haven't tested it. I don't have a WiFi shield.