Feature request (and small bug): Add mouse wheel to key binding options

[Esteban Villanova]

I would like to use the mousewheel to change track height. This is very useful! 

Also there's a bug with the vertical zoom tool. If there's any track selected besides from the first one, if you click and drag down and back up, you end up all tracks hidden above the visible area so you have to scrool up again.

 

Thanks!