YITH Booking and Appointment for WooCommerce Premium 5.18.0

* New - support to WooCommerce 3.6.0 RC 1
* Update - language files
* Update - YITH Booking theme 1.1.3
* Fix - integration with Multi Vendor: issue when associating a booking service to vendors
* Fix - price calculation with fixed duration
* Fix - prevent memory issues
* Tweak - check for booking availability directly in cart
* Tweak - added product link in error cart message
* Tweak - improved performances
* Dev - added yith_wcbk_request_confirmation_login_required_notice filter
* Dev - added yith_wcbk_booking_product_calculated_price_totals_formatted filter

New - completely redesigned product settings panel to improve the plugin usability and to make it easier to set up booking products
New - extra costs
New - weekly discount
New - monthly discount
New - last minute discount
New - extra price for every person added to a specified value
New - possibility to show details about booking price totals on frontend
New - create a people type directly in product page (via AJAX)
New - create services directly in product page (via AJAX)
New - multiply base price by number of people
New - multiply fixed base fee by number of people
New - tooltip in booking service shortcode
Update - YITH Booking theme 1.1.2
Update - language files
Fix - WPML integration
Fix - availability time range issue
Fix - availability rule issue when overriding a non-bookable rule
Fix - js date issue on calendar on due to Daylight Saving Time
Fix - search form results when there are hourly and per-minute booking products
Fix - removed arguments in product links in search form results on hourly and per-minute booking products
Fix - cache issue on non-available dates with external service synchronization
Fix - added service quantities when paying for booking that requires confirmation
Fix - integration with YITH WooCommerce Deposits and Down Payments: prevent deposits on request confirmation bookings
Fix - issue when counting people as separate booking
Fix - person type counting issue in booking form when checking for availability
Fix - person types issue in Booking form
Fix - issue when translating 'View cart' text
Fix - show people type only if published
Tweak - improved Booking Form style
Dev - WooCommerce CRUD for Booking products
Dev - added yith_wcbk_booking_product_last_minute_discount_applied_on filter
Dev - added yith_wcbk_booking_product_calculated_price_totals filter
Dev - added yith_wcbk_product_get_not_available_dates filter

Update - plugin framework
Update - language files
Fix - warning when saving product