persist object scale / rotation / position

src/mesh/group.js

@@ -77,10 +77,8 @@ mesh.group = class MeshGroup extends mesh.object {
         // auto-remove group when empty
         if (this.group.children.length === 0) {
             mesh.api.group.remove(this);
-            // update worker state
-            worker.object_destroy({id: this.id});
-            // update object store
-            mesh.db.space.remove(this.id);
+            // manage lifecycle with worker, mesh app caches, etc
+            this.destroy();
         } else {
             // update data store
             mesh.db.space.put(this.id, this.models.map(m => m.id));