Fixed bg-music glitches.

Vocaluxe/Lib/Sound/Playback/CAudioStreamBase.cs

@@ -36,6 +36,11 @@ namespace Vocaluxe.Lib.Sound.Playback
             get { return _ID; }
         }
 
+        public bool IsFading
+        {
+            get { return _Fading != null; }
+        }
+
         public virtual float Volume { get; set; }
         public virtual float VolumeMax { get; set; }
         public virtual float Length { get; protected set; }

Vocaluxe/Lib/Sound/Playback/CPlaybackBase.cs

@@ -74,7 +74,8 @@ namespace Vocaluxe.Lib.Sound.Playback
                 return;
             float volumeF = volume.Clamp(0, 100) / 100f;
             foreach (IAudioStream stream in _Streams)
-                stream.VolumeMax = volumeF;
+                if(!stream.IsFading)
+                    stream.VolumeMax = volumeF;
             _GlobalVolume = volumeF;
         }
 

Vocaluxe/Lib/Sound/Playback/IAudioStream.cs

@@ -28,6 +28,7 @@ namespace Vocaluxe.Lib.Sound.Playback
     public interface IAudioStream : IDisposable
     {
         int ID { get; }
+        bool IsFading { get; }
         float Volume { get; set; }
         float VolumeMax { get; set; }
         float Length { get; }