Feature request: slider/key for hiding layers above a certain elevation and adjusting z_scale

[ElectricPotato]

I wanted to look at the layers individually, so I changed 'data' in the javascript in the generated html file to not be a const and repeatedly executed data=data.slice(0,-1) in the javascript console to hide the top most layers. It would be nice if this was made into a feature, e.g. press 'Q' to move the view down a layer and 'E' to go up a layer.

a way to edit z_scale would also be nice, setting z_scale to a small value like 0.0000000000001 removes perspective (as was mentioned in another issue) and a large value like 0.0001 makes the view 'explode' which is cool to look at in 3D