added arduino, modified build

arduino/libraries/SoftPWM/examples/SoftPWM_Wiring_HeartBeat/SoftPWM_Wiring_HeartBeat.pde

@@ -0,0 +1,30 @@
+#include <SoftPWM.h>
+
+#ifndef WLED
+#define WLED LED_BUILTIN
+#endif
+
+void setup()
+{
+  SoftPWMBegin();
+
+  // Sets the PWM value to 0 for the built-in LED (WLED).
+  SoftPWMSet(WLED, 0);
+  
+  // Sets the default fade time for WLED to
+  // 100 ms fade-up and 550 ms to fade-down.
+  SoftPWMSetFadeTime(WLED, 100, 550);
+}
+
+void loop() 
+{
+  // Turn on WLED
+  SoftPWMSet(WLED, 255);
+  // Wait for the fade-up and some extra delay.
+  delay(250);
+  // Turn off WLED
+  SoftPWMSet(WLED, 0);
+  // Wait for the fade-down, and some extra delay.
+  delay(650);
+}
+