3D Viewer: use 'wheel' event instead of 'mousewheel'
3D Viewer: use 'wheel' event instead of 'mousewheel'

The 'wheel' event is standarized and replaces the non-standard
'mousewheel' in DOM Level 3, all major browsers support it:

https://developer.mozilla.org/en-US/docs/Web/Events/wheel

This is related to acardona/CATMAID#972.

fzadow/CATMAID,fzadow/CATMAID,fzadow/CATMAID,fzadow/CATMAID