ex05: added intesect_triangle(), get_color() and light sources
ex05: get color/normal information from mesh
ex05: save image to disk
ex05: added print() macro
ex05: added toRGB() conversion
ex05: added specular light in blinn/phon
ex05: always raytrace on startup
ex05: raytrace (at least a little bit)
ex05: change light settings