Added a new renderer called PathTracer

Which does global illumination by path tracing :)
bugfix for my previous commit
Move lights to model and add image parameters to config file.
ModelIntersection handles lights

And the old GetModelIntersection is renamed to GetObjectIntersection.
Fix for previous commit.
Refactor meshes to geometry

Also rename ObjectIntersection to GeometryIntersection
Add rectangle generator.
Refactor PathTracer
Add platonic solid generators.
Merge branch 'master' of github.com:kovacsv/RayTracer
Set back development config file.
Merge branch 'master' into UserInterface