WooCommerce One Page Checkout 2.8.1

* Fix: Fix issues with compatibility with Name Your Price introduced with v1.5.0.
* Fix: Update .pot file for translations.

* New: Add improved support for Name Your Price extension - support Product Table, Pricing Table, and Single Product templates. PR#272
* WooCommerce 3.0: Fix display of product attributes for variation products. PR#274
* Fix: do not nest additional .opc_order_review divs for each Ajax load. PR#277
* Fix: Handle Grouped OPC products correctly rather than always triggering a "Sorry, this product cannot be purchased" error. PR#278
* Fix: Make sure "Ship to a different address" checkbox is available when it should be, which also fixes Apple Pay compatibility. PR#276

* WooCommerce 3.0: Fix autofocus/page scroll by removing the new 'autofocus' attribute on the first name checkout form when WooCommerce 3.0+ is active. PR#267
* WooCommerce 3.0: Fix image display on single product product selection template.
* WooCommerce 3.0: Fix use of deprecated 'wc_add_to_cart_message'.