Unwrap Event Exceptions

This was a useless exception wrapper that ends up making
stack traces harder to read as well as the JVM cutting off
the important parts

Nothing catches this exception, so its safe to just get rid
of it and let the REAL exception bubble down

Spigot-API-Patches/0059-Entity-fromMobSpawner.patch

@@ -0,0 +1,26 @@
+From e5a62fbf4f51754de1e49ce6046eefc76c317a73 Mon Sep 17 00:00:00 2001
+From: BillyGalbreath <Blake.Galbreath@GMail.com>
+Date: Sun, 18 Jun 2017 18:17:05 -0500
+Subject: [PATCH] Entity#fromMobSpawner()
+
+
+diff --git a/src/main/java/org/bukkit/entity/Entity.java b/src/main/java/org/bukkit/entity/Entity.java
+index 015a4c56..13de2d74 100644
+--- a/src/main/java/org/bukkit/entity/Entity.java
++++ b/src/main/java/org/bukkit/entity/Entity.java
+@@ -569,5 +569,12 @@ public interface Entity extends Metadatable, CommandSender, Nameable {
+      * @return Location where entity originates or null if not yet added
+      */
+     Location getOrigin();
++
++    /**
++     * Returns whether this entity was spawned from a mob spawner.
++     *
++     * @return True if entity spawned from a mob spawner
++     */
++    boolean fromMobSpawner();
+     // Paper end
+ }
+-- 
+2.20.1
+