Update from upstream SpigotMC

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

CraftBukkit-Patches/0067-Log-Cause-of-Unexpected-Exceptions.patch

@@ -0,0 +1,24 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: md_5 <git@md-5.net>
+Date: Wed, 18 Dec 2013 13:39:14 +1100
+Subject: [PATCH] Log Cause of Unexpected Exceptions
+
+
+diff --git a/src/main/java/net/minecraft/server/MinecraftServer.java b/src/main/java/net/minecraft/server/MinecraftServer.java
+index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
+--- a/src/main/java/net/minecraft/server/MinecraftServer.java
++++ b/src/main/java/net/minecraft/server/MinecraftServer.java
+@@ -0,0 +0,0 @@ public abstract class MinecraftServer implements ICommandListener, Runnable, IMo
+             }
+         } catch (Throwable throwable) {
+             i.error("Encountered an unexpected exception", throwable);
++            // Spigot Start
++            if ( throwable.getCause() != null )
++            {
++                i.error( "\tCause of unexpected exception was", throwable.getCause() );
++            }
++            // Spigot End
+             CrashReport crashreport = null;
+ 
+             if (throwable instanceof ReportedException) {
+--