Issues #19 #12 #14: Derived a better esitmate in order to normalize the brdf - by t0. Further added an approach for specular light - for fragment shader an approximative constant version, for the vertex shader a summation approximation. NB: multiply light with a white point d65 asap in matlab for colorization. also added some test date and further enhanced camera constant constructur in order to provide a orthogonal camera set up - see computation of cop inside the constructor.