[BLB] Implement Jolly Gerbils

Mage/src/main/java/mage/game/events/GameEvent.java

@@ -668,6 +668,12 @@ public class GameEvent implements Serializable {
          playerId   player who foraged
          */
         FORAGED,
+        /* gave a gift
+         targetId   the player who received the gift
+         sourceId   of the ability
+         playerId   player who gave the gift
+         */
+        GAVE_GIFT,
         //custom events
         CUSTOM_EVENT
     }