Unit on Build is Generic. (half way there)

OpenRA.Game/Traits/HasUnitOnBuild.cs

@@ -0,0 +1,35 @@
+
+using System;
+
+namespace OpenRA.Traits
+{
+
+	class HasUnitOnBuildInfo : ITraitInfo
+	{
+		public readonly string Unit = null;
+		public readonly string InitialActivity = null;
+		public readonly int2 SpawnOffset = int2.Zero;
+		public readonly int Facing = 0;
+		
+		public object Create( Actor self ) { return new HasUnitOnBuild(self); }
+	}
+
+	public class HasUnitOnBuild
+	{
+		
+		public HasUnitOnBuild(Actor self)
+		{
+			var info = self.Info.Traits.Get<HasUnitOnBuildInfo>();
+			
+			self.World.AddFrameEndTask(
+				w =>
+				{
+					var unit = w.CreateActor(info.Unit, self.Location 
+						+ info.SpawnOffset, self.Owner);
+					var unitTrait = unit.traits.Get<Unit>();
+					unitTrait.Facing = info.Facing;
+					//unit.QueueActivity( new Harvest() );
+				});
+		}
+	}
+}