add configurable fanpower for simwind and new PWM sketch (#37)

src/arduino/simwind_pwm/simwind.h

@@ -0,0 +1,15 @@
+#ifndef _SIMWINDDATA_H
+#define _SIMWINDDATA_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+typedef struct
+{
+    uint8_t velocity;
+    uint8_t fanpower;
+}
+SimWindData;
+
+
+#endif