Let activities know when they are being run for the first or last time

OpenRA.Game/Settings.cs

@@ -92,6 +92,7 @@ namespace OpenRA
 		public bool SanityCheckUnsyncedCode = false;
 		public int Samples = 25;
 		public bool IgnoreVersionMismatch = false;
+		public bool StrictActivityChecking = false;
 		public bool SendSystemInformation = true;
 		public int SystemInformationVersionPrompt = 0;
 		public string UUID = System.Guid.NewGuid().ToString();