Handle Lighting parameters when rendering colors

[proyan]

Hi Guys,

OpenGL proposes the following lighting parameters for rendering objects: ambient, diffuse, specular and emissive. These are explained in http://www.glprogramming.com/red/chapter05.html
Allowing this in gepetto-viewer should be possible with the current API.

This is a tracker issue, meant to keep this development in check.
Best,
Rohan

[jmirabel]

This is purely a matter of forwarding the data correctly. It should be easy to achieve by using node properties.