WooCommerce Smart Coupons 9.18.0

* New: WooCommerce 3.4.2 compatibility
* Fix: PHP Notice: Undefined variable: smart_coupons_block
* Fix: Error: Call to member function 'get_id' on boolean when updating order
* Fix: Store Credit deducting everytime when order status is updated from order admin page
* Update: Enabled Free Shipping, Usage Limit (Per Coupon, Per User) field for Store Credit
* Update: Apply remaining balance of store credit to renewal order even if it is less than renewal order total [WooCommerce Subscription]
* Update: POT File

* Update: Remove Order Personal data on WooCommerce hook
* Update: Query to handle lengthy data
* Update: Remove debug code
* Update: Text domain
* Update: POT file

* New: [GDPR] Privacy Policy Content
* New: [GDPR] Personal Data Export (WordPress 4.9.6+)
* New: [GDPR] Personal Data Erase (WordPress 4.9.6+)
* Update: Hook to decide whether to auto-generate a coupon or not
* Update: Hook to decide whether to show coupon as valid or invalid
* Update: Import-Export of coupon usage data
* Update: Minor CSS (Admin Send Store Credit tab)
* Update: POT file