Fix various Mods.Common animation traits not supporting actors having multiple sprite bodies

OpenRA.Mods.Common/Traits/Render/WithIdleAnimation.cs

@@ -9,6 +9,7 @@
  */
 #endregion
 
+using System.Linq;
 using OpenRA.Traits;
 
 namespace OpenRA.Mods.Common.Traits.Render
@@ -21,6 +22,9 @@ namespace OpenRA.Mods.Common.Traits.Render
 
 		public readonly int Interval = 750;
 
+		[Desc("Which sprite body to play the animation on.")]
+		public readonly string Body = "body";
+
 		public override object Create(ActorInitializer init) { return new WithIdleAnimation(init.Self, this); }
 	}
 
@@ -33,7 +37,7 @@ namespace OpenRA.Mods.Common.Traits.Render
 		public WithIdleAnimation(Actor self, WithIdleAnimationInfo info)
 			: base(info)
 		{
-			wsb = self.Trait<WithSpriteBody>();
+			wsb = self.TraitsImplementing<WithSpriteBody>().Single(w => w.Info.Name == Info.Body);
 			buildComplete = !self.Info.HasTraitInfo<BuildingInfo>(); // always render instantly for units
 			ticks = info.Interval;
 		}