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/DigitalIO/examples/testSoftSPI/testSoftSPI.ino

@@ -0,0 +1,37 @@
+// Scope test for development - assumes 328 processor.
+#include <DigitalIO.h>
+
+const uint8_t SOFT_SPI_MISO_PIN = 7;
+const uint8_t SOFT_SPI_MOSI_PIN = 8;
+const uint8_t SOFT_SPI_SCK_PIN  = 9;
+const uint8_t SPI_MODE = 0;
+
+SoftSPI<SOFT_SPI_MISO_PIN, SOFT_SPI_MOSI_PIN, SOFT_SPI_SCK_PIN, SPI_MODE> spi;
+
+int test;
+void setup() {
+  Serial.begin(9600);
+  spi.begin();
+  while(1) {
+    Serial.println("Enter:");
+    Serial.println("R - Receive");
+    Serial.println("S - Send");
+    Serial.println("T - Transfer");
+    while ((test = Serial.read()) <= 0) {}
+    test = toupper(test);
+    if (strchr("RST", test)) break;
+    Serial.println("Invalid entry");
+  };
+  Serial.print("Starting test ");
+  Serial.println((char)test);
+}
+void loop() {
+  if (test == 'S') spi.send(0X55);
+  if (test == 'R') {
+    Serial.println(spi.receive(), HEX);
+  }
+  if (test == 'T') {
+    Serial.println(spi.transfer(0XAA), HEX);
+  }
+  delay(10);
+}