Intermediary commit. Nothing's working, everything is broken. Let's start over now...

include/controller.h

@@ -1,13 +1,15 @@
 #pragma once
 
 #include "player.h"
+#include "sd_card.h"
 
 class Controller {
 private:
 	Player* _player;
+	SDCard* _sd_card;
 
 public:
-	Controller(Player* p) : _player(p) {}
+	Controller(Player* p, SDCard* c) : _player(p), _sd_card(c) {}
 	void vol_up();
 	void vol_down();
 	void track_next();