Change "stopped with error" symbol from warn to fatal

environment.go

@@ -279,7 +279,7 @@ func (this *environment) run(actor Actor) {
 				if this.Verb() { log.Printf("(i) [%s] stopped", typ) }
 			}
 		} else {
-			log.Printf("!!! [%s] stopped with error: %v", typ, stopErr)
+			log.Printf("XXX [%s] stopped with error: %v", typ, stopErr)
 			if this.flags.crashOnError {
 				panic(fmt.Sprint(stopErr))
 			}