Feature/basic osg shader2

rebased
getSrgbColor, it seems that this code is not executed, because you renamed getColorsRGB in the base classe. btw does this class is usefu ? I mean maybe we can't remove it, and use a debug compiler to show normal/uvs, this kind of things. If it's not needed now we could do it later.
I still understand that it makes sense to make a little compiler at least to see how things fit together.