Add ScriptUpgradesCache class to enable maps to explicitly declare what upgrades their Lua scripts will use

OpenRA.Mods.Common/Scripting/ScriptUpgradesCache.cs

@@ -0,0 +1,33 @@
+#region Copyright & License Information
+/*
+ * Copyright 2007-2015 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 OpenRA.Traits;
+
+namespace OpenRA.Mods.Common.Scripting
+{
+	[Desc("Allows granting upgrades to actors from Lua scripts.")]
+	public class ScriptUpgradesCacheInfo : ITraitInfo
+	{
+		[Desc("Upgrades that can be granted from the scripts.")]
+		public readonly string[] Upgrades = { };
+
+		public object Create(ActorInitializer init) { return new ScriptUpgradesCache(this); }
+	}
+
+	public sealed class ScriptUpgradesCache
+	{
+		public readonly ScriptUpgradesCacheInfo Info;
+
+		public ScriptUpgradesCache(ScriptUpgradesCacheInfo info)
+		{
+			Info = info;
+		}
+	}
+}