Added options panel and affiliate tag redirection

This change adds the ability to include an affiliate program ID in the request, which is worth substantially more than smile (smile is about .5%, while affiliate offers 3-8%). The best part is that both can be used for now, but I added a toggle to disable the redirect to smile in case that changes for some reason.

Feedback is welcome!

Here are some details from the Amazon FAQ:

Can I earn advertising fees by sending traffic to smile.amazon.com?
Yes. Amazon Associates can earn advertising fees for Qualifying Purchases completed on smile.amazon.com. Amazon Associates do not need to register separately for AmazonSmile - Amazon Associates can use the same Associates ID they use for affiliate links to www.amazon.com. If your organization is an eligible 501(c)(3) public charitable organization, you may register for both programs and earn AmazonSmile donations as well as Amazon Associates advertising fees. To learn more about registering for AmazonSmile as a charitable organization, visit the AmazonSmile Org Central.


How do I create affiliate links to AmazonSmile?
You can create affiliate text links to AmazonSmile by changing the domain in an affiliate link URL from “www.amazon.com” to “smile.amazon.com” while keeping everything else in the URL exactly the same as your standard affiliate links. Currently, all links created using Associates Central tools send traffic to pages on www.amazon.com. Many of the links created using our tools can be edited to point to smile.amazon.com, though some cannot. Associates can’t edit a destination URL for Widgets, Banners and Text and Image product links—URLs created by these tools can’t be changed to send users to AmazonSmile at this time.


Can charitable organizations participate in both AmazonSmile and the Amazon Associates program?
Yes. You can participate in both programs if you are a 501(c)(3) public charitable organization and meet the AmazonSmile program eligibility criteria. For complete details, visit the AmazonSmile Org Central.