YITH WooCommerce Composite Products Premium 1.30.0

* New: WordPress 5.1 support
* Update: YIT Plugin Framework 3.2.1
* Fix: Per-Item Pricing option for variable products
* Fix: Minor bugs

* New: WordPress 5.1 support
* New: WooCommerce 3.6 support
* Update: Dutch language
* Update: YIT Plugin Framework 3.1.28
* Fix: Variable products discount
* Fix: Order again with product components
* Fix: Quantity 0 cart problem
* Fix: Out of stock components selection
* Fix: Out of stock variations selection
* Fix: Tax panel hidden in edit product
* Fix: Notice of "product_parent_id"
* Fix: Minor bugs

* New: Product links in thumbnail view
* Update: Language file
* Update: YIT Plugin Framework 3.1.17
* Update: Language files
* Dev: Added stock class to the thumbnails view
* Fix: Component variation price reset
* Fix: Component variations table style
* Fix: Product Base Price value
* Fix: Minor bugs