apply bg music options changes immediately

Vocaluxe/Base/CBackgroundMusic.cs

@@ -91,5 +91,13 @@ namespace Vocaluxe.Base
                 }
             }
         }
+
+        public static void ApplyVolume()
+        {
+            for (int i = 0; i < _BackgroundMusicStreams.Count; i++)
+			{
+			    CSound.SetStreamVolume(_BackgroundMusicStreams[i], CConfig.BackgroundMusicVolume); 
+			}
+        }
     }
 }

Vocaluxe/Screens/CScreenOptionsSound.cs

@@ -128,7 +128,14 @@ namespace Vocaluxe.Screens
         private void SaveConfig()
         {
             CConfig.BackgroundMusic = (EOffOn)SelectSlides[htSelectSlides(SelectSlideBackgroundMusic)].Selection;
+
+            if (CConfig.BackgroundMusic == EOffOn.TR_CONFIG_ON)
+                CBackgroundMusic.Play();
+            else
+                CBackgroundMusic.Pause();
+
             CConfig.BackgroundMusicVolume = SelectSlides[htSelectSlides(SelectSlideBackgroundMusicVolume)].Selection * 5;
+            CBackgroundMusic.ApplyVolume();
 
             CConfig.SaveConfig();
         }