~ Added: message for function "Buy Course via Product."
~ Fixed: error items cannot be added to LP Order when WC Order is completed by some host without enabling background; will run manually rather than through background.
~ Supported: the shortcode [learn_press_button_course].
~ Fixed: js - with more buttons add to cart on single, archive course.
~ Added: LP Order key on WC order
~ Fixed: error when buy course and product on same order.
