Zooming is a bit bumpy

[mvindahl]

When zooming across several zoom levels there is an impression of "bumpiness". This is caused by the zooming coming to a temporary stop until it receives a new mouse wheel event. This should be fixable by detecting mouse wheel events during the final phase when zooming from one level to another, and if they are of a certain magnitude, just continue zooming once the destination has been reached.

Or figure out an alternative solution.