[Request] Favicons for groups

I LOVE this extension. It does exactly what I needed.

You currently have a little panorama-button icon next to each group. It would be so sweet if that icon instead displayed the favicon from the first tab in each group.

Currently most of my groups share the same favicon across the group (because they are related). I could switch between groups a lot faster if I didn't have to read the text to see which group I was switching to.