Added W5100S for W5100S Ethernetshield

[taylor-an]

WIZnet has launched a new chip W5100S. And W5100S Ethernetshiled is developing for ARDUINO.

You can see the sheet of comparison between W5100 on WIZwiki >Products >iEthernet >W5100S >Comparison Sheet.

[CLAassistant]

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Requested change made. Thanks!

[taylor-an]

I've signed. Thank you.