Moved SelectionDecorations to Mods.Common

And added more settings.

Moved SelectionBoxRenderable to Mods.Common, too.

OpenRA.Game/Traits/TraitsInterfaces.cs

@@ -110,6 +110,16 @@ namespace OpenRA.Traits
 
 	public interface ISeedableResource { void Seed(Actor self); }
 
+	public interface ISelectionDecorations
+	{
+		ISelectionDecorationsInfo SelectionDecorationsInfo { get; }
+	}
+
+	public interface ISelectionDecorationsInfo
+	{
+		int[] SelectionBoxBounds { get; }
+	}
+
 	public interface IVoiced
 	{
 		string VoiceSet { get; }