[UNF] "Name Sticker" Goblin, [WHO] Coward // Killer, [WHO] Thijarian Witness (#11392)

* Add [WHO] Coward // Killer

* Add MTGO version of [UNF] "Name Sticker" Goblin

* Implement [WHO] Thijarian Witness

* Add NameStickerGoblinTest

* Fix Thijarian Witness, add tests (may need additional tests). Also adds a simple toString for MageObjectReference

* Don't spam the java garbage collector, add another test

* Replace non-ASCII characters in card text

* improve MOR toString

* Thijarian Witness fixed better, add AttackingBlockingWatcher in common

* cleanup from xenohedron's review

* Fix test, add warning not to use AttackingBlockingWatcher for static effects

* rename AttackingBlockingWatcher to AttackingBlockingDelayedWatcher to make it more obvious how it should be used, minor documentation changes
Simplify and rename Thijarian Witness Predicate

* add null checks

Mage/src/main/java/mage/MageObjectReference.java

@@ -100,6 +100,10 @@ public class MageObjectReference implements Comparable<MageObjectReference>, Ser
         }
     }
 
+    @Override
+    public String toString(){
+        return "("+zoneChangeCounter+"|"+sourceId.toString().substring(0,3)+")";
+    }
     public UUID getSourceId() {
         return sourceId;
     }