Ebay - Add links to similar and suggested items

Adds links to Ebay's "Items similar to X" and "Recommendations for X" pages to all item pages, appearing as icons above the "Seller information" block on the right-hand side of the page - see the screenshot.

Changelog

1.2.1 (13.07.2018)

• Update linting options and globals
• Update jQuery to v3 hosted on unpkg.com

1.2.0

• Now also adds buttons on pages when the listing has ended