Implement scroll wheel for zooming in new validation UI?

[jonfroehlich]

Could save clicks and be more efficient/seamless. Also matches how GSV works.

[misaugstad]

I'm guessing that it wouldn't be too hard to do what we're doing now with the scroll wheel.

If we wanted to have a more continuous zoom with the scroll wheel, I'd need to do some digging and a lot of testing to make sure that our whole pipeline would work with the different zoom levels. The integer zoom levels may have been set on purpose due to how we download panos/crops from Google.

[misaugstad]

We talked about this briefly at a 1:1 and consider it to be low priority.