Auctions for WooCommerce 3.1

* Add: seated auctions
* Add: shortcode to display parts of the template, [auctions_templates template="add-to-cart|bid|pay|bid-form|condition|countdown|max-bid|reserve|auction-sealed|ajax-conteiner-start|ajax-conteiner-end|auctions_seated_progressbar_template"]

* Fix: warning triggered by auctions_for_woocommerce_outbid hook bug
* Fix: template shortcode return instead of echo content
* Fix: db version set to 3.0

• WooCommerce rest api problem