This method is a bit more optimized than the very first one
because it does not rely on the adjacent faces properties.
That said it's still a bit slower than the per vertex method.
This make the limited wireframe not a performance problem anymore.
However, this does change the number of edges displayed as the threshold
is now computed per vertex instead of per edges.
For this reason we extended (internaly) the range of the slider so that the
users can hide more edge.
This overlay is showing mesh topology. It is usable with transparency
even if the mesh order can mess up with the expected result (some object
more prominent than others).
Edge thickness and alpha values are hardcoded for now but can easily be
added to theme or object settings.
