Update from upstream SpigotMC

Upstream merge (we must go deeper) SpigotMC/Spigot@1e7bc383c3

CraftBukkit-Patches/0159-Fix-Null-Tile-Entity-Worlds.patch

@@ -0,0 +1,19 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: "Evan A. Haskell" <eah2119@gmail.com>
+Date: Thu, 26 Jun 2014 18:37:29 -0400
+Subject: [PATCH] Fix Null Tile Entity Worlds
+
+
+diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
+index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
+--- a/src/main/java/net/minecraft/server/World.java
++++ b/src/main/java/net/minecraft/server/World.java
+@@ -0,0 +0,0 @@ public abstract class World implements IBlockAccess {
+                     }
+                 }
+ 
++                tileentity.a(this); // Spigot - No null worlds
+                 this.a.add(tileentity);
+             } else {
+                 this.tileEntityList.add(tileentity);
+--