mu3: added lights hook

mu3io/serialimpl.h

@@ -0,0 +1,15 @@
+/*
+    Serial LED implementation for chuniio
+    
+    Credits:
+    somewhatlurker, skogaby
+*/
+
+#pragma once
+
+#include <windows.h>
+
+#include "mu3io/leddata.h"
+
+HRESULT mu3_led_serial_init(wchar_t led_com[12], DWORD baud);
+void mu3_led_serial_update(struct _ongeki_led_data_buf_t* data);