Add group of products to cart from table view
1. A user opens a category page and sees a list of products from the category
2. He switches to Table display mode
4. The users selects multiple products in the product list. When he selects a product with an empty QTY field, the field is filled with "1" number. When he unticks a product, the field is emptied. The users adds to cart selected products by clicking "Buy selected" button. The button behaves in a way similar to the one how a regular "add to cart" button behaves.