YITH WooCommerce Auctions Premium 4.8.0

* New: Support to WooCommerce 3.7.0 RC2

* Tweak: Show auction start and end time on backend in WordPress timezone
* Tweak: Add new parameter to the filter yith_wcact_get_price_for_customers
* Tweak: Show auction data on backend using the same dateformat as frontend
* Tweak: Check if the product is auction before send the email
* Tweak: Add new parameters to the yith_wcact_shortcode_catalog_orderby filter
* Update: Italian language
* Update: plugin-fw
* Update: Pot file
* Dev: filter yith_wcact_winner_email_pay_now_url

* Fix: enqueue correct script for shortcodes
* Dev: filter yith_wcact_actual_bid_add_value
* Dev: filter yith_wcact_load_auction_price_html
* Dev: filter yith_wcact_check_bid_increment

* New: Support to WooCommerce 3.6.0 RC2
* Update: Plugin-Fw
* Update: Dutch language
* Tweak: add woocommerce_before_add_to_cart_button on auction template
* Dev: action yith_wcact_auction_end_start
* Dev: filter yith_wcact_check_if_add_bid