Migrate various thinkers to plain objects.

WIP: Gib models currently in progress.
WIP: IK re-rigging of Demolitionist in progress.

zscript/handler/swwm_handler_process.zsc

@@ -153,7 +153,13 @@ extend Class SWWMHandler
 			if ( swwm_notrack )
 			{
 				int n = trackers_cnt;
-				while ( trackers ) trackers.Destroy(); // wow that's simple, all in one line
+				while ( trackers )
+				{
+					let next = trackers.next;
+					trackers.Destroy(); // wow that's simple, all in one line
+					trackers = next;
+				}
+				trackers_cnt = 0;
 				Console.Printf("%d trackers removed.",n);
 			}
 			else
@@ -717,5 +723,4 @@ extend Class SWWMHandler
 		}
 		return false;
 	}
-
 }