Merge 2.27.89 - 2.29.94
fixed bug of JError not found when creating category with not supported image type in New Category Page fixed bugs of warning messages of two undefined variables showing in all pages fixed bugs of warning messages in categories tree page - for both cases: when there is data and when there is no data fixed bugs of warning messages in new category page fixed bugs of warning messages in products list page - in both cases for both cases: when there is data and when there is no data fixed bugs of warning messages in new product page