Dispose some sound streams.

OpenRA.Mods.Common/AudioLoaders/AudLoader.cs

@@ -51,13 +51,14 @@ namespace OpenRA.Mods.Common.AudioLoaders
 		}
 	}
 
-	public class AudFormat : ISoundFormat
+	public sealed class AudFormat : ISoundFormat
 	{
 		public int Channels { get { return 1; } }
 		public int SampleBits { get { return 16; } }
 		public int SampleRate { get { return sampleRate; } }
 		public float LengthInSeconds { get { return AudReader.SoundLength(stream); } }
 		public Stream GetPCMInputStream() { return new MemoryStream(rawData.Value); }
+		public void Dispose() { stream.Dispose(); }
 
 		int sampleRate;
 		Lazy<byte[]> rawData;