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/UIPUdp.h

@@ -25,15 +25,20 @@
 #include <Udp.h>
 #include "utility/mempool.h"
 extern "C" {
-  #include "utility/uip.h";
+  #include "utility/uip.h"
 }
 
 #define UIP_UDP_MAXDATALEN 1500
 #define UIP_UDP_PHYH_LEN UIP_LLH_LEN+UIP_IPUDPH_LEN
 #define UIP_UDP_MAXPACKETSIZE UIP_UDP_MAXDATALEN+UIP_UDP_PHYH_LEN
-#ifndef UIP_UDP_NUMPACKETS
-#define UIP_UDP_NUMPACKETS 5
-#endif
+
+typedef struct {
+  memaddress out_pos;
+  memhandle packet_next;
+  memhandle packet_in;
+  memhandle packet_out;
+  boolean send;
+} uip_udp_userdata_t;
 
 class UIPUDP : public UDP
 {
@@ -41,14 +46,7 @@ class UIPUDP : public UDP
 private:
   struct uip_udp_conn *_uip_udp_conn;
 
-  struct appdata_t
-  {
-    memaddress out_pos;
-    memhandle packets_in[UIP_UDP_NUMPACKETS];
-    memhandle packet_in;
-    memhandle packet_out;
-    boolean send;
-  } appdata;
+  uip_udp_userdata_t appdata;
 
 public:
   UIPUDP();  // Constructor
@@ -120,7 +118,9 @@ private:
 
   friend void uipudp_appcall(void);
 
-  static void uip_callback();
+  friend class UIPEthernetClass;
+  static void _send(uip_udp_userdata_t *data);
+
 };
 
 #endif