Control/Shift/Alt scroll wheel configuration when using image viewer

[Leo]

@PerlLlama

If I can ask for one more thing - This might be a macro rather than a preferences option,

When viewing an image in full screen, I would like 'ESC' to exit full screen mode.
Once in window mode, a ESC would then exit the viewer as it already does.

I've split that into a separate thread:

Make Esc in viewer exit fullscreen

This might be a macro rather than a preferences option. When viewing an image in full screen, I would like 'ESC' to exit full screen mode. Once in window mode, a ESC would then exit the viewer as it already does.