Spigot patch 0035: Prevent NPE in CraftSign

This commit prevents the constructor of CraftSign throwing an NPE when it cannot get the sign tile entity. Instead it will fallback to a 4 empty lined sign, and not try to do anything to those lines on .update().

https://github.com/EcoCityCraft/Spigot/blob/d9c76252eb02f7d0d6bea11efe77e3bb1edb0d99/CraftBukkit-Patches/0035-Prevent-NPE-in-CraftSign.patch
Spigot patch 0036: Stage DataWatcher & WatchableObject.

So that we may identify the exact cause of exceptions originating from these classes.

https://github.com/EcoCityCraft/Spigot/blob/d9c76252eb02f7d0d6bea11efe77e3bb1edb0d99/CraftBukkit-Patches/0036-Stage-DataWatcher-WatchableObject.patch