Add CashTricklerMultiplier

OpenRA.Mods.Common/TraitsInterfaces.cs

@@ -308,6 +308,9 @@ namespace OpenRA.Mods.Common.Traits
 		string SequencePrefix { get; }
 	}
 
+	[RequireExplicitImplementation]
+	public interface ICashTricklerModifier { int GetCashTricklerModifier(); }
+
 	[RequireExplicitImplementation]
 	public interface IDamageModifier { int GetDamageModifier(Actor attacker, Damage damage); }