Update of CSettings.cs for BackgroundMusic

Vocaluxe/Base/CSettings.cs

@@ -71,6 +71,7 @@ namespace Vocaluxe.Base
         public const string sFolderSounds = "Sounds";
         public const string sFolderLanguages = "Languages";
         public const string sFolderScreenshots = "Screenshots";
+        public const string sFolderBackgroundMusic = "BackgroundMusic";
 
         //public const String[] ToneStrings = new String[]{ "C", "C#", "D", "D#", "E", "F", "F#", "G", "G#", "A", "A#", "B" };
         public const int ToneMin = -36;