Add new scene controller with touch display example.

Upgraded RF24 to latest version which supports SoftSPI. 
Added DigitalIO and UTFT libraries to support the new example.
Fix problem reported in RelayWithButtonActuator example.

libraries/UIPEthernet/UIPServer.cpp

@@ -28,12 +28,12 @@ UIPServer::UIPServer(uint16_t port) : _port(htons(port))
 
 UIPClient UIPServer::available()
 {
-  UIPEthernet.tick();
+  UIPEthernetClass::tick();
   for ( uip_userdata_t* data = &UIPClient::all_data[0]; data < &UIPClient::all_data[UIP_CONNS]; data++ )
     {
       if (data->packets_in[0] != NOBLOCK
           && (((data->state & UIP_CLIENT_CONNECTED) && uip_conns[data->state & UIP_CLIENT_SOCKETS].lport ==_port)
-              || ((data->state & UIP_CLIENT_CLOSED) && ((uip_userdata_closed_t *)data)->lport == _port)))
+              || ((data->state & UIP_CLIENT_REMOTECLOSED) && ((uip_userdata_closed_t *)data)->lport == _port)))
         return UIPClient(data);
     }
   return UIPClient();
@@ -42,7 +42,7 @@ UIPClient UIPServer::available()
 void UIPServer::begin()
 {
   uip_listen(_port);
-  UIPEthernet.tick();
+  UIPEthernetClass::tick();
 }
 
 size_t UIPServer::write(uint8_t c)