Restructure PaperSpigot as a new set of modules

Allows us much greater control over the Spigot portion of the code
and makes us more "proper"
Credit to @Dmck2b for originally passing the idea along a while back

CraftBukkit-Patches/0120-Properly-cancel-fishing-event.-Fixes-BUKKIT-5396.patch

@@ -0,0 +1,24 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: "gjmcferrin@gmail.com" <gjmcferrin@gmail.com>
+Date: Mon, 10 Feb 2014 10:05:11 -0500
+Subject: [PATCH] Properly cancel fishing event. Fixes BUKKIT-5396
+
+Previously, when cancelling a PlayerFishEvent with State.FISHING, the next
+fishing attempt would automatically result in a new PlayerFishEvent with
+State.FAILED_ATTEMPT because the player's hooked entity was not properly
+cleared. This ensures that the player's hooked entity value is set to null so
+that the next attempt will result in the proper state being called.
+
+diff --git a/src/main/java/net/minecraft/server/ItemFishingRod.java b/src/main/java/net/minecraft/server/ItemFishingRod.java
+index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
+--- a/src/main/java/net/minecraft/server/ItemFishingRod.java
++++ b/src/main/java/net/minecraft/server/ItemFishingRod.java
+@@ -0,0 +0,0 @@ public class ItemFishingRod extends Item {
+             world.getServer().getPluginManager().callEvent(playerFishEvent);
+ 
+             if (playerFishEvent.isCancelled()) {
++                entityhuman.hookedFish = null;
+                 return itemstack;
+             }
+             // CraftBukkit end
+--