Remove Selectable boolean from Selectable trait

Add work-around for ta/td bridge huts since they need actor Bounds to
be targetable by C4/engineer repair.

OpenRA.Mods.Common/Traits/CustomSelectionSize.cs

@@ -0,0 +1,36 @@
+#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 System;
+using OpenRA.Traits;
+
+namespace OpenRA.Mods.Common.Traits
+{
+	[Desc("Special case trait for invisible, unselectable actors like bridge huts.",
+	"Gives actor targetable area for special cases like C4 and engineer repair.",
+	"This trait conflicts with AutoSelectionSize so you cannot use both, and doesn't support custom offsets.")]
+	public class CustomSelectionSizeInfo : ITraitInfo
+	{
+		public readonly int[] CustomBounds = null;
+
+		public object Create(ActorInitializer init) { return new CustomSelectionSize(this); }
+	}
+
+	public class CustomSelectionSize : IAutoSelectionSize
+	{
+		readonly CustomSelectionSizeInfo info;
+		public CustomSelectionSize(CustomSelectionSizeInfo info) { this.info = info; }
+
+		public int2 SelectionSize(Actor self)
+		{
+			return new int2(info.CustomBounds[0], info.CustomBounds[1]);
+		}
+	}
+}