Shuffle the playlist before playing if "[random]" is in the rfid data.

include/controller.h

@@ -19,13 +19,13 @@ class Controller {
 	unsigned long button_pressed_since = 0;
 	bool button_already_processed = false;
 	String read_rfid_data();
-	
+
 	public:
 	void handle();
 	void next_track();
 	void prev_track();
 	void play();
-	void play(String rfid_id);
+	void play(String rfid_id, bool shuffle=false);
 	void stop();
 	void eof_mp3();
 };

include/playlist.h

@@ -22,4 +22,5 @@ class Playlist {
 	void restart();
 	void set_current_time(uint32_t time);
 	uint32_t get_current_time();
+	void shuffle();
 };