WooCommerce Smart Coupons 9.18.0

* New: Allow printing of coupons
* Fix: Missing parameter in hook 'woocommerce_email_styles'
* Update: POT file

* New: Merge 'Send Store Credit' tab with 'Bulk Generate' tab
* New: Preview email while bulk generating coupons
* Update: Coupon display text for WooCommerce Subscriptions coupon types
* Update: POT file

* New: Feature to enable 'auto-apply' for a coupon
* New: Tested upto WooCommerce 3.9.1
* Fix: Uncaught TypeError: Cannot read property 'fragments' of undefined during checkout
* Fix: 'Send store credit' failing to send email when 'Combined Emails' is enabled
* Fix: Store credit getting deducted twice when applied on backend
* Fix: Validate coupon before attempting to apply from cookie (URL coupon)
* Fix: Product for purchasing credit getting added to cart with zero price
* Fix: Showing error 'Coupon was used in another transaction, and coupon usage limit is reached'
* Update: Responsive template for purchasing credit
* Update: Use sentence case for coupon fields in admin
* Update: Minor changes
* Update: POT file