YITH WooCommerce Wishlist Premium 4.0.1

* New: added support to WooCoommerce 3.5
* New: added support to WordPress 4.9.8
* New: added method that returns localization variables
* New: updated plugin framework
* Tweak: type attribute from <script> tag
* Update: Spanish language
* Update: Italian language
* Dev: added new filter yith_wcwl_localize_script to let third party dev filter localization variables
* Dev: added new filter yith_wcwl_column_default
* Dev: added new filter yith_wcwl_wishlist_column
* Dev: added new filter yith_wcwl_share_conditions to display the share buttons for no logged users
* Dev: added new filter yith_wcwl_set_cookie to let third party code skip cookie saving
* Dev: added new filter yith_wcwl_wishlist_visibility_string_value to the wishlist visibility value
* Dev: added new filter yith_wcwl_manage_wishlist_title
* Dev: added new filter yith_wcwl_create_wishlist_title
* Dev: added new filter yith_wcwl_search_wishlist_title
* Dev: added new filter yith_wcwl_result_wishlist
* Dev: added new filter yith_wcwl_empty_search_result
* Dev: added new filter yith_wcwl_wishlist_param to change query-string param
* Dev: added new filter yith_wcwl_remove_product_wishlist_message_title

* New: WooCommerce 3.4 compatibility
* New: WordPress 4.9.6 compatibility
* New: updated plugin framework
* New: GDPR compliance
* New: register dateadded field for the lists
* Tweak: replaced create_function with a proper class method, to improve compatibility with PHP 7.2 and avoid warnings
* Fix: js error when switching from Premium version to Free
* Fix: preventing add_rewrite_rule when WPML is active, to avoid possible Internal Server Error (thanks to Adri & Bruno)
* Fix: icon replacement not working on variable Add to Cart
* Fix: preventing warning "Illegal string offset" when get_availability() returns empty string instead of array
* Update: Italian language
* Dev: added filter yith_wcwl_redirect_url
* Dev: added filter yith_wcwl_login_notice

New: tested with WooCommerce 3.3.0
Fix: issue with Add to Wishlist shortcode when global $product not defined