Commenting out MarchingCubes out of SceneUtils.cloneObject.

As a reminded that we need to move all that to the objects themselves...

src/extras/SceneUtils.js

@@ -113,11 +113,13 @@ THREE.SceneUtils = {
 
 			object = new THREE.LOD();
 
-		} else if ( THREE.MarchingCubes && source instanceof THREE.MarchingCubes ) {
+		/*
+		} else if ( source instanceof THREE.MarchingCubes ) {
 
 			object = new THREE.MarchingCubes( source.resolution, source.material );
 			object.field.set( source.field );
 			object.isolation = source.isolation;
+		*/
 
 		} else if ( source instanceof THREE.Object3D ) {