This commit adds support for '+' and 'Z' for "zoom in" and '-' and 'z'
for "zoom out" shortcut keys in the lightbox image viewer for Pan and
Zoom.
Fixes: #8689.
This fixes the lightbox zoom issues that occurred on some browsers
due to the units of `deltaY` being in lines rathern than pixels,
making it incredibly slow to zoom.
This makes the canvas zoom and pan feature cross-browser compatible in
a few ways:
1. Replace deprecated `mousewheel` event in favor of the similar and
cross-browser event `wheel`.
2. Create approximate substitute for `e.movementX` and `e.movementY`
values that are missing in Safari.
Abhigyan Khaund
Tim Abbott
Brock Whittaker