Update CraftBukkit to Minecraft 1.3.1

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

@@ -11,11 +11,7 @@ public class WorldGenForest extends WorldGenerator implements BlockSapling.TreeG
     }
 
     public boolean a(World world, Random random, int i, int j, int k) {
-        // CraftBukkit start
-        // sk: The idea is to have (our) WorldServer implement
-        // BlockChangeDelegate and then we can implicitly cast World to
-        // WorldServer (a safe cast, AFAIK) and no code will be broken. This
-        // then allows plugins to catch manually-invoked generation events
+        // CraftBukkit start - moved to generate
         return this.generate((BlockChangeDelegate) world, random, i, j, k);
     }