Remove base world gen, not needed since a world will be supplied in my usecase

src/main/java/net/jstom/Main.java

@@ -29,9 +29,6 @@ public class Main {
         // Create the instance
         InstanceContainer instanceContainer = instanceManager.createInstanceContainer();
         // Set the ChunkGenerator
-        instanceContainer.setGenerator(unit -> 
-            unit.modifier().fillHeight(0, 40, Block.GRASS_BLOCK)
-        );
         instanceContainer.setChunkSupplier(LightingChunk::new);
 
         // Add an event callback to specify the spawning instance (and the spawn position)