[Feedback Request] Top Sites Styling

[PanopticaRising]

I threw together a quick Widget to request optional permissions for the TopSites API.

I'm not sure how to style it at this point. Chrome doesn't expose Thumbnail information, but Firefox should, so I'm also not sure how to best handle that difference.

My branch is here. (I'd like to get around to adding some of the options that Firefox has for the API, as well as the numbering and styling, but I'd rather aim for a smaller subset of acceptability for PR.)