Move all include files to src/include

- 86Box's own headers go to /86box
- munt's public interface goes to /mt32emu
- all slirp headers go to /slirp (might want to consider using only its public inteface)
- single file headers from other projects go in include root

src/sio_fdc37c669.c

@@ -18,18 +18,18 @@
 #include <stdlib.h>
 #include <string.h>
 #include <wchar.h>
-#include "86box.h"
-#include "86box_io.h"
-#include "timer.h"
-#include "device.h"
-#include "pci.h"
-#include "lpt.h"
-#include "serial.h"
-#include "hdc.h"
-#include "hdc_ide.h"
-#include "fdd.h"
-#include "fdc.h"
-#include "sio.h"
+#include <86box/86box.h>
+#include <86box/io.h>
+#include <86box/timer.h>
+#include <86box/device.h>
+#include <86box/pci.h>
+#include <86box/lpt.h>
+#include <86box/serial.h>
+#include <86box/hdc.h>
+#include <86box/hdc_ide.h>
+#include <86box/fdd.h>
+#include <86box/fdc.h>
+#include <86box/sio.h>
 
 
 typedef struct {