Refactor: replaced sourceId by source and introduced source param in some methods;

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

@@ -0,0 +1,21 @@
+package mage.game.events;
+
+import mage.abilities.Ability;
+
+import java.util.UUID;
+
+/**
+ * @author JayDi85
+ */
+public class DrawCardsEvent extends GameEvent {
+
+    public DrawCardsEvent(UUID playerId, Ability source, GameEvent originalDrawEvent, int amount) {
+        super(GameEvent.EventType.DRAW_CARDS, playerId, source, playerId, amount, false);
+
+        // source of draw events must be kept between replacements, example: UnpredictableCycloneTest
+        if (originalDrawEvent != null) {
+            this.addAppliedEffects(originalDrawEvent.getAppliedEffects());
+            this.setSourceId(originalDrawEvent.getSourceId());
+        }
+    }
+}