Refactored IQuantizeBodyOrientation implementation

Moved BodyOrientation and related interfaces from Game to Mods.Common.
Introduced QuantizeFacingsFromSequence trait.
With*Body render traits no longer implement IQuantizeBodyOrientation
themselves.

OpenRA.Mods.Common/Traits/QuantizeFacingsFromSequence.cs

@@ -0,0 +1,43 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2015 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;
+using System.Collections.Generic;
+using System.Linq;
+using OpenRA.Graphics;
+using OpenRA.Mods.Common.Graphics;
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.Common.Traits
+{
+	[Desc("Derive facings from sprite body sequence.")]
+	public class QuantizeFacingsFromSequenceInfo : UpgradableTraitInfo, IQuantizeBodyOrientationInfo, Requires<RenderSpritesInfo>
+	{
+		[Desc("Defines sequence to derive facings from."), SequenceReference]
+		public readonly string Sequence = "idle";
+
+		public int QuantizedBodyFacings(ActorInfo ai, SequenceProvider sequenceProvider, string race)
+		{
+			if (string.IsNullOrEmpty(Sequence))
+				throw new InvalidOperationException("Actor " + ai.Name + " is missing sequence to quantize facings from.");
+
+			var rsi = ai.Traits.Get<RenderSpritesInfo>();
+			return sequenceProvider.GetSequence(rsi.GetImage(ai, sequenceProvider, race), Sequence).Facings;
+		}
+
+		public override object Create(ActorInitializer init) { return new QuantizeFacingsFromSequence(this); }
+	}
+
+	public class QuantizeFacingsFromSequence : UpgradableTrait<QuantizeFacingsFromSequenceInfo>
+	{
+		public QuantizeFacingsFromSequence(QuantizeFacingsFromSequenceInfo info)
+			: base(info) { }
+	}
+}