added arduino, modified build

arduino/libraries/Adafruit_Circuit_Playground/examples/mega_demo/RainbowCycleDemo.h

@@ -0,0 +1,40 @@
+#ifndef RAINBOWCYCLEDEMO_H
+#define RAINBOWCYCLEDEMO_H
+
+#include "Demo.h"
+
+// Animation speeds to loop through with mode presses.  The current milliseconds 
+// are divided by this value so the smaller the value the faster the animation.
+static int speeds[] = { 5, 10, 50, 100 };
+
+class RainbowCycleDemo: public Demo {
+public:
+  RainbowCycleDemo() { currentSpeed = 0; }
+  ~RainbowCycleDemo() {}
+
+  virtual void loop() {
+    // Make an offset based on the current millisecond count scaled by the current speed.
+    uint32_t offset = millis() / speeds[currentSpeed];
+    // Loop through each pixel and set it to an incremental color wheel value.
+    for(int i=0; i<10; ++i) {
+      CircuitPlayground.strip.setPixelColor(i, CircuitPlayground.colorWheel(((i * 256 / 10) + offset) & 255));
+    }
+    // Show all the pixels.
+    CircuitPlayground.strip.show();
+  }
+
+  virtual void modePress() {
+    // Increment through the available speeds.
+    currentSpeed += 1;
+    if (currentSpeed >= sizeof(speeds)/sizeof(int)) {
+      currentSpeed = 0;
+    }
+  }
+
+private:
+  int currentSpeed;
+  
+};
+
+
+#endif