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/0031-Firework-Meta-Crash-Fix.patch

@@ -0,0 +1,29 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: md_5 <md_5@live.com.au>
+Date: Sat, 15 Jun 2013 21:34:48 +1000
+Subject: [PATCH] Firework Meta Crash Fix
+
+
+diff --git a/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaFirework.java b/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaFirework.java
+index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
+--- a/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaFirework.java
++++ b/src/main/java/org/bukkit/craftbukkit/inventory/CraftMetaFirework.java
+@@ -0,0 +0,0 @@ class CraftMetaFirework extends CraftMetaItem implements FireworkMeta {
+             case BURST:
+                 return 4;
+             default:
+-                throw new AssertionError(type);
++                throw new IllegalStateException(type.toString()); // Spigot
+         }
+     }
+ 
+@@ -0,0 +0,0 @@ class CraftMetaFirework extends CraftMetaItem implements FireworkMeta {
+             case 4:
+                 return Type.BURST;
+             default:
+-                throw new AssertionError(nbt);
++                throw new IllegalStateException(Integer.toString(nbt)); // Spigot
+         }
+     }
+ 
+--