* Add functions related with "MAC Address of WIZ550io"
  in Ethernet.cpp & Ethernet.h
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#if defined(WIZ550io_WITH_MACADDRESS)
  // Initialize function when use the ioShield serise (included WIZ550io)
  // WIZ550io has a MAC address which is written after reset.
  // Default IP, Gateway and subnet address are also writen.
  // so, It needs some initial time. please refer WIZ550io Datasheet in details.
  int begin(void);
  void begin(IPAddress local_ip);
  void begin(IPAddress local_ip, IPAddress dns_server);
  void begin(IPAddress local_ip, IPAddress dns_server, IPAddress gateway);
  void begin(IPAddress local_ip, IPAddress dns_server, IPAddress gateway, IPAddress subnet);
#endif
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* Change '#include <Twitter.h>' to '#include "./Twitter.h"'
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#include "./Twitter.h" // Twitter.h in library/Ethernet folder. @diffinsight 2013-08-19
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* Add Difine
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#define WIZ550io_WITH_MACADDRESS // Use assigned MAC address of WIZ550io
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