Editor: Simplified fog handling

Author: mrdoob

editor/js/Editor.js

@@ -132,8 +132,7 @@ Editor.prototype = {
 		this.scene.name = scene.name;
 
 		this.scene.background = scene.background;
-
-		if ( scene.fog !== null ) this.scene.fog = scene.fog.clone();
+		this.scene.fog = scene.fog;
 
 		this.scene.userData = JSON.parse( JSON.stringify( scene.userData ) );