proc comes with 2 free silos; fix silo/proc prereq

OpenRA.Mods.RA/ReplaceWithActor.cs

@@ -0,0 +1,43 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007,2009,2010 Chris Forbes, Robert Pepperell, Matthew Bowra-Dean, Paul Chote, Alli Witheford.
+ * This file is part of OpenRA.
+ * 
+ *  OpenRA is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ * 
+ *  OpenRA is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ * 
+ *  You should have received a copy of the GNU General Public License
+ *  along with OpenRA.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#endregion
+
+using OpenRA.Graphics;
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.RA
+{
+	class ReplaceWithActorInfo : ITraitInfo
+	{
+		public readonly string Actor = null;
+		public object Create(Actor self) { return new ReplaceWithActor(self, this); } 
+	}
+
+	class ReplaceWithActor
+	{
+		public ReplaceWithActor(Actor self, ReplaceWithActorInfo info)
+		{
+			self.World.AddFrameEndTask(w =>
+			{
+				w.Remove(self);
+				w.CreateActor(info.Actor, self.Location, self.Owner);
+			});
+		}
+	}
+}