3D-Viewer: parameterize raytracing lights, add it to options dialog
I parameterized the raytracing lights so they can be edited instead of using the hard-coded configuration.
The default values results on the same light color and positions than the previous hard-coded version.
I removed some hacks related to PostProcessing. Since the improvements on !284 (merged) and with more control of the lights or future options, this hacks can be removed. Also resulting on a more correct light render.