Add library request: ESP8266-ping

[bluemurder]

Hello,
I recently created a library for ESP8266 platform, to provide easy access to Ping functionalities.

The code is very simple but it can be useful to test in an efficient way the connectivity to/from other IP devices able to forward icmp responses.

The url related to such library is https://github.com/bluemurder/esp8266-ping

Best regards,
Alessio

[cmaglie]

done