implement the fact chunk for WAVE files

OpenRA.FileFormats/FileFormats/WavLoader.cs

@@ -32,6 +32,9 @@ namespace OpenRA.FileFormats
 
 		public readonly int ListChunkSize;
 
+		public readonly int FactChunkSize;
+		public readonly int Samples;
+
 		public WavLoader(Stream s)
 		{
 			while (s.Position < s.Length)
@@ -69,6 +72,10 @@ namespace OpenRA.FileFormats
 						ListChunkSize = s.ReadInt32();
 						s.ReadBytes(ListChunkSize); // Ignore annotation meta data.
 						break;
+					case "fact":
+						FactChunkSize = s.ReadInt32();
+						Samples = s.ReadInt32();
+						break;
 					default:
 						throw new NotSupportedException("{0} chunks are not supported.".F(type));
 				}