Added internal MC support for multiple worlds

src/main/java/net/minecraft/server/WorldManager.java

@@ -0,0 +1,39 @@
+package net.minecraft.server;
+
+public class WorldManager implements IWorldAccess {
+
+    private MinecraftServer a;
+    public WorldServer world; // Craftbukkit
+
+    // Craftbukkit - changed signature
+    public WorldManager(MinecraftServer minecraftserver, WorldServer world) {
+        this.a = minecraftserver;
+        this.world = world;
+    }
+
+    public void a(String s, double d0, double d1, double d2, double d3, double d4, double d5) {}
+
+    public void a(Entity entity) {
+        this.a.k.a(entity);
+    }
+
+    public void b(Entity entity) {
+        this.a.k.b(entity);
+    }
+
+    public void a(String s, double d0, double d1, double d2, float f, float f1) {}
+
+    public void a(int i, int j, int k, int l, int i1, int j1) {}
+
+    public void a() {}
+
+    public void a(int i, int j, int k) {
+        this.a.f.a(i, j, k, world); // Craftbukkit
+    }
+
+    public void a(String s, int i, int j, int k) {}
+
+    public void a(int i, int j, int k, TileEntity tileentity) {
+        this.a.f.a(i, j, k, tileentity);
+    }
+}