YITH WooCommerce Product Add-ons Premium 4.18.0

* New: "First X options free" feature
* New: "Hide Label" setting for add-on options
* New: Support to "Variable subscription" products
* Update: YIT Plugin Framework 3.0.20
* Tweak: Improved WPML compatibility
* Fix: Add-ons position in variable products
* Fix: Vendor settings in groups
* Fix: Show Options shortcode
* Fix: Main image replacement
* Fix: Filter to disable the plugin init
* Fix: Groups categories with WPML
* Fix: Minor bugs

* New: Option to enable/disable general "collapse" feature
* New: Option to collapse each single add-on
* Dev: New filter to disable the plugin init
* Dev: New filter to disable the jQuery UI loading
* Dev: New filter to hide add-ons group container
* Dev: New filter "yith_wapo_show_group_container"
* Update: Dutch language file
* Fix: Check for catalog mode hiding price
* Fix: Fatal error after update
* Fix: Minor bugs

• New: WordPress 4.9.6 support
• New: WooCommerce 3.4 support
• New: Support to GDPR compliance
• New: Privacy class
• Update: Spanish translation
• Update: Italian translation
• Update: Dutch translation
• Fix: Options image placeholder
• Fix: "Required" title in add-on name
• Fix: Add-ons image replacement
• Fix: Plugin localization loading
• Fix: Price percentage of a variable product with "Select" type
• Fix: Translation required title
• Fix: Minor bugs