Renames keyboard folder to keyboards, adds couple of tmk's fixes (#432)

* fixes from tmk's repo

* rename keyboard to keyboards

keyboards/jd45/jd45.h

@@ -0,0 +1,13 @@
+#ifndef JD45_H
+#define JD45_H
+
+#include "matrix.h"
+#include "keymap.h"
+#include "backlight.h"
+#include <stddef.h>
+#include <avr/io.h>
+
+void matrix_init_user(void);
+void matrix_scan_user(void);
+
+#endif