OBJ file format.

For this raytracer I chose to import the OBJ file format as the easiest one to parse.
So here is the first draft implementation of the importing of vertex positions.
This simple code is ready to use, the form is: (take-vertexes "test-file.obj")

Random rays.

Trying to generate random rays, I have got a problem.
Basically I had few ways to get a 'random' vector or in other words a random point on the surface of the unit sphere.