support mouse zoom in

[Nambers]

Like that function in lightroom - we can click the mouse once to zoom into 100%, and one back to fitting.
E.g. https://github.com/sachinchoolur/lg-zoom support double click on images to see it's actual size in JS

[cbenning]

It's been a while, but if you're still interested in this issue try out the v3 branch I'm working on. It will be released soon:

https://github.com/cbenning/fussel/tree/v3