Adds back displaying the currently playing song as such in the queue

We no longer alter the song, the queue gets this from the player.
That way we can't have two songs marked as 'playing' at the same time.

app/queue/queue.js

@@ -32,4 +32,10 @@ angular.module('jamstash.queue.controller', ['jamstash.player.service'])
     $scope.removeSelectedSongsFromQueue = function () {
         player.removeSongs($scope.selectedSongs);
     };
+
+    $scope.isPlayingSong = function (song) {
+        return angular.equals(song, player.getPlayingSong());
+    };
+
+    //TODO: Hyz: updateFavorite - leave in rootScope ?
 }]);