Better low stock level alert emails and more fixes

We normally reserved the changelog for large feature announcements but we’ll do our best from now on to include all changes and fixes to bring about more transparency to the product.

Low stock level alert email subject lines will now sometimes contain more information
Re-arranging your inventory with a CSV file is now faster performance-wise
Fixed an issue where stock on Etsy going above maximum limit wasn’t being handled properly
Fixed new eBay sales channels not being authorized properly