ProductBulkLoader issue when creating category pages

[elliot-sawyer]

The ProductBulkLoader importer chokes at L182 this when create_new_product_groups is set to true:

Object->__call(): the method 'setTitle' does not exist on 'SilverShop\Page\ProductCategory'

The setTitle method indeed does not exist. I've fixed it in a subclassed importer for my own needs, but is there any reason I could not use $obj->Title = $title; instead? Happy to raise a pull request since it seems like a minor fix