YITH Frontend Manager for WooCommerce Premium 1.45.0

* Fix: Unable to delete coupons with all roles in WooCommerce 3.6.x

* New: Support for WooCommerce 3.6
* Update: Italian language
* Update: Spanish language
* Tweak: Code refactoring for products section
* Tweak: Code refactoring for coupons section
* Tweak: Add unique id for product taxonomies wrapper in add/edit product template
* Tweak: Replace update_post_meta with WooCommerce setters method
* Fix: Save issue with YITH WooCommerce Featured Audio and Video Content and WooCommerce 3.6
* Fix: Invoice button style
* Fix: Unable to disabled SMS Notification section
* Fix: No fired action for new product created
* Fix: Error on update billing and shippng information if vendor haven't access to this information
* Fix: Show empty taxonomy box for vendors
* Dev: yith_wcfm_skip_taxonomy hook to skip show taxonomy in add/edit product

New: Support for YITH Auctions for WooCommerce
Fix: Actions url on stock report
Fix: No titles for action buttons on Stock Report
Fix: Prevent to print empty menu item is no label set
Fix: Wrong link for user on commission details page