added SellOrderGenerator

OpenRa.Game/Orders/SellOrderGenerator.cs

@@ -0,0 +1,37 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using OpenRa.Game.GameRules;
+using OpenRa.Game.Traits;
+
+namespace OpenRa.Game.Orders
+{
+	class SellOrderGenerator : IOrderGenerator
+	{
+		public IEnumerable<Order> Order(int2 xy, MouseInput mi)
+		{
+			var loc = mi.Location + Game.viewport.Location;
+			var underCursor = Game.FindUnits(loc, loc)
+				.Where( a => a.traits.Contains<Building>() ).FirstOrDefault();
+
+			if (underCursor != null && !underCursor.Info.Selectable)
+				underCursor = null;
+
+			if (underCursor == null)
+				yield break;
+
+			var building = underCursor.traits.Get<Building>();
+			if (building.unitInfo.Unsellable)
+				yield break;
+
+			if (underCursor.Owner != Game.LocalPlayer)
+				yield break;
+
+			yield return new Order("Sell", underCursor, null, int2.Zero, null);
+		}
+
+		public void Tick() {}
+		public void Render() {}
+	}
+}