Woocommerce GoCardless 2.9.3

* Tweak - Default subscription order and renewal order to processing. Filters provided to override the initial order status.
* Fix - Make sure to check if `get_current_screen` function exists in which the wrapper might be called in non-admin page.
* Fix - Incorrect filter name for create redirect flow params.

* Fix - Added support for WooCommerce 3.0 and compatibility with older versions.
* Fix - Fatal error caused by calling empty cart during renewal order.

* Fix - Before payment is confirm, order status should be on-hold instead of processing.
* Fix - Truncate the description sent to GoCardless if over 100 characters.
* Fix - Added support for WooCommerce 2.7 and compatibility with older versions.
* Fix - Issue where recurring payment indicator in Subscriptions setting does not show GoCardless supports that.
* Enhancement - Added support for Subscriptions switching support.
* Fix - Makes HTTPS in redirect URI and webhook endpoint is requirement.