Add a contrast color mode for screenshots dedicated to be shown in a presentation

[panquez]

Showing a mesh or model in a presentation os difficult, since we should have high contrast (light color of faces and dark and bold for edges for instance) for a good visibility.

I suppose this should be a non-necessarily very accessible option, so I would put it in a menu or setting panel ?

[panquez]

Or maybe in a screenshot dedicated route. In order to not have to change the ongoing working graphical options