Make IntervalTimer stub so simulator works

simulation/include/interrupts.h

@@ -0,0 +1,17 @@
+#ifndef __INTERRUPTS_H
+#define __INTERRUPTS_H
+
+//Dummy functions, used by macros for interrupts() / noInterrupts()
+void __enable_irq() {}
+void __disable_irq() {}
+
+
+struct IntervalTimer
+{
+    public:
+        IntervalTimer() {};
+        bool begin(void (*funct)(), unsigned int microseconds) { };
+
+};
+
+#endif