Added new PlayerExpChangeEvent and PlayerLevelChangeEvent events. Thanks to feildmaster for the PR.

src/main/java/org/bukkit/event/player/PlayerExpChangeEvent.java

@@ -0,0 +1,43 @@
+package org.bukkit.event.player;
+
+import org.bukkit.entity.Player;
+import org.bukkit.event.HandlerList;
+
+/**
+ * Called when a players experience changes naturally
+ */
+public class PlayerExpChangeEvent extends PlayerEvent {
+    private static final HandlerList handlers = new HandlerList();
+    private int exp;
+
+    public PlayerExpChangeEvent(Player player, int expAmount) {
+         super(Type.PLAYER_EXP_CHANGE, player);
+         exp = expAmount;
+    }
+
+    /**
+     * Get the amount of experience the player will receive
+     *
+     * @return The amount of experience
+     */
+    public int getAmount() {
+        return exp;
+    }
+
+    /**
+     * Set the amount of experience the player will receive
+     *
+     * @param amount The amount of experience to set
+     */
+    public void setAmount(int amount) {
+        exp = amount;
+    }
+
+    public HandlerList getHandlers() {
+        return handlers;
+    }
+
+    public static HandlerList getHandlerList() {
+        return handlers;
+    }
+}