Changed the playing code to use Playlists managed by a PlaylistManager. This allows you to have randomized playlists and stuff. Also, you can now access special functions via the contents of RFID tags. See the README for a list of available modes.

include/playlist_manager.h

@@ -0,0 +1,14 @@
+#pragma once
+
+#include <map>
+#include "playlist.h"
+
+class PlaylistManager {
+private:
+	std::map<String, String> _map;
+	std::map<String, Playlist*> _playlists;
+public:
+	PlaylistManager();
+	Playlist* get_playlist_for_id(String id);
+	void dump_ids();
+};