Mark design review files as viewed

We're doing the hard work so your eyeballs can focus on what's important. You can now mark files in a design review as viewed. You won't have to look at them again unless you want to or you receive a notification that they've changed.

We've even added a counter to tell you how many files are in review, and how many you've viewed.

We also include the number of pending comments in the review button so you can see what's pending.