Rewrite sequence loading logic.

Multiple layers of Lazy<T>ness are replaced with
an explicit two-part loading scheme.

Sequences are parsed immediately, without the need
for the sprite assets, and tell the SpriteCache
which frames they need. Use-cases that want the
actual sprites can then tell the SpriteCache to
load the frames and the sequences to resolve the
sprites.

OpenRA.Mods.Common/TraitsInterfaces.cs

@@ -35,7 +35,7 @@ namespace OpenRA.Mods.Common.Traits
 
 	public interface IQuantizeBodyOrientationInfo : ITraitInfoInterface
 	{
-		int QuantizedBodyFacings(ActorInfo ai, SequenceProvider sequenceProvider, string race);
+		int QuantizedBodyFacings(ActorInfo ai, SequenceSet sequences, string faction);
 	}
 
 	public interface IPlaceBuildingDecorationInfo : ITraitInfoInterface