Remove patch #15 - optimized chunk unload

By: md_5 <md_5@live.com.au>

CraftBukkit-Patches/0020-Handle-Null-Tile-Entities.patch

@@ -0,0 +1,27 @@
+From e7535637a11b98cd8eebd8909b19c4000370203f Mon Sep 17 00:00:00 2001
+From: md_5 <md_5@live.com.au>
+Date: Sun, 3 Feb 2013 09:20:19 +1100
+Subject: [PATCH] Handle Null Tile Entities
+
+
+diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
+index 75402e7..fd76af0 100644
+--- a/src/main/java/net/minecraft/server/World.java
++++ b/src/main/java/net/minecraft/server/World.java
+@@ -1334,6 +1334,13 @@ public abstract class World implements IBlockAccess {
+ 
+         while (iterator.hasNext()) {
+             TileEntity tileentity = (TileEntity) iterator.next();
++            // Spigot start
++            if (tileentity == null) {
++                getServer().getLogger().severe("Spigot has detected a null entity and has removed it, preventing a crash");
++                iterator.remove();
++                continue;
++            }
++            // Spigot end
+             // CraftBukkit start - Don't tick entities in chunks queued for unload
+             ChunkProviderServer chunkProviderServer = ((WorldServer) this).chunkProviderServer;
+             if (chunkProviderServer.unloadQueue.contains(tileentity.x >> 4, tileentity.z >> 4)) {
+-- 
+1.8.1.2
+