Remove unused and obsolete Cached.cs

This was similar to Lazy<T>

OpenRA.Game/OpenRA.Game.csproj

@@ -281,7 +281,6 @@
     <Compile Include="Primitives\ActionQueue.cs" />
     <Compile Include="Primitives\Bits.cs" />
     <Compile Include="Primitives\Cache.cs" />
-    <Compile Include="Primitives\Cached.cs" />
     <Compile Include="Primitives\DisposableAction.cs" />
     <Compile Include="Primitives\float2.cs" />
     <Compile Include="Primitives\int2.cs" />

OpenRA.Game/Primitives/Cached.cs

@@ -1,55 +0,0 @@
-#region Copyright & License Information
-/*
- * Copyright 2007-2011 The OpenRA Developers (see AUTHORS)
- * This file is part of OpenRA, which is free software. It is made
- * available to you under the terms of the GNU General Public License
- * as published by the Free Software Foundation. For more information,
- * see COPYING.
- */
-#endregion
-
-using System;
-
-namespace OpenRA.Primitives
-{
-	public class Cached<T>
-	{
-		Func<T> p;
-		T value;
-		bool hasValue;
-
-		public Cached(Func<T> p)
-		{
-			if (p == null)
-				throw new ArgumentNullException();
-
-			this.p = p;
-		}
-
-		public T Value
-		{
-			get
-			{
-				if (hasValue)
-					return value;
-
-				value = p();
-				hasValue = true;
-				return value;
-			}
-		}
-
-		public T Force() { return Value; }
-
-		public void Invalidate()
-		{
-			hasValue = false;
-		}
-	}
-
-	public static class Cached
-	{
-		public static Cached<T> New<T>(Func<T> p) { return new Cached<T>(p); }
-	}
-}
-