Store Messages 1.0.0

First release.

• Send a message from any WooCommerce order: shipped (tracking), ready for pickup, item unavailable, refund issued, order delayed, payment reminder, review request, personal message — or your own templates.
• Templates and the email layout are plain HTML in a code editor with live desktop/mobile preview, real or sample order data, and test sends.
• "Note to customer" emails use the same layout; a pasted tracking link becomes a Track your package button.
• Optionally mark the order Completed while sending, without WooCommerce's extra Order complete email.
• Tracking shown in My account and WooCommerce emails; every send logged as a private order note and on the Activity tab.
• Updates from GitHub through WordPress's normal Update now.