Implement greatly expanded ChunkGenerator API

This new API:
* Has first class support for Material / MaterialData
* Abstracts away the underlying Chunk format
* Implements useful utility methods to make life easier

By: Antony Riley <antony@cyberiantiger.org>

paper-api/src/main/java/org/bukkit/Server.java

@@ -38,6 +38,7 @@ import org.bukkit.util.CachedServerIcon;
 
 import com.avaje.ebean.config.ServerConfig;
 import com.google.common.collect.ImmutableList;
+import org.bukkit.generator.ChunkGenerator;
 
 import org.bukkit.inventory.ItemFactory;
 import org.bukkit.inventory.meta.ItemMeta;
@@ -914,6 +915,17 @@ public interface Server extends PluginMessageRecipient {
      */
     public int getIdleTimeout();
 
+    /**
+     * Create a ChunkData for use in a generator.
+     * 
+     * See {@link ChunkGenerator#generateChunkData(org.bukkit.World, java.util.Random, int, int, org.bukkit.generator.ChunkGenerator.BiomeGrid)}
+     * 
+     * @param world the world to create the ChunkData for
+     * @return a new ChunkData for the world
+     * 
+     */
+    public ChunkGenerator.ChunkData createChunkData(World world);
+
     /**
      * @see UnsafeValues
      * @return the unsafe values instance