Use BlockCommandSender for dispatching Command block commands

Also allow commands that don't start with a / to match vanilla behavior

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

@@ -9,7 +9,7 @@ public class TileEntity {
 
     private static Map a = new HashMap();
     private static Map b = new HashMap();
-    protected World world;
+    public World world; // CraftBukkit - protected -> public
     public int x;
     public int y;
     public int z;