Convert yaml-exposed facings to WAngle.

OpenRA.Mods.Common/Traits/Production.cs

@@ -56,8 +56,8 @@ namespace OpenRA.Mods.Common.Traits
 				var spawn = self.CenterPosition + exitinfo.SpawnOffset;
 				var to = self.World.Map.CenterOfCell(exit);
 
-				var initialFacing = WAngle.FromFacing(exitinfo.Facing);
-				if (exitinfo.Facing < 0)
+				WAngle initialFacing;
+				if (!exitinfo.Facing.HasValue)
 				{
 					var delta = to - spawn;
 					if (delta.HorizontalLengthSquared == 0)
@@ -68,6 +68,8 @@ namespace OpenRA.Mods.Common.Traits
 					else
 						initialFacing = delta.Yaw;
 				}
+				else
+					initialFacing = exitinfo.Facing.Value;
 
 				exitLocations = rp.Value != null && rp.Value.Path.Count > 0 ? rp.Value.Path : new List<CPos> { exit };