split Sound.cs in smaller chunks

OpenRA.Game/Sound/NullSound.cs

@@ -0,0 +1,50 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2014 The OpenRA Developers (see AUTHORS)
+ * This file is part of OpenRA, which is free software. It is made
+ * available to you under the terms of the GNU General Public License
+ * as published by the Free Software Foundation. For more information,
+ * see COPYING.
+ */
+#endregion
+
+using System;
+
+namespace OpenRA
+{
+	class NullSoundEngine : ISoundEngine
+	{
+		public NullSoundEngine()
+		{
+			Console.WriteLine("Using Null sound engine which disables SFX completely");
+		}
+
+		public ISoundSource AddSoundSourceFromMemory(byte[] data, int channels, int sampleBits, int sampleRate)
+		{
+			return new NullSoundSource();
+		}
+
+		public ISound Play2D(ISoundSource sound, bool loop, bool relative, WPos pos, float volume, bool attenuateVolume)
+		{
+			return new NullSound();
+		}
+
+		public void PauseSound(ISound sound, bool paused) { }
+		public void StopSound(ISound sound) { }
+		public void SetAllSoundsPaused(bool paused) { }
+		public void StopAllSounds() { }
+		public void SetListenerPosition(WPos position) { }
+		public void SetSoundVolume(float volume, ISound music, ISound video) { }
+
+		public float Volume { get; set; }
+	}
+
+	class NullSoundSource : ISoundSource { }
+
+	class NullSound : ISound
+	{
+		public float Volume { get; set; }
+		public float SeekPosition { get { return 0; } }
+		public bool Playing { get { return false; } }
+	}
+}