new C++ demo: realtime.cc (real-time scene viewer using SDL) Quaternion, Camera::rotate and Camera::move replace all printf's with infomsg wrapper don't allocate memory in Raytracer::render, just blindly write to provided address don't creat Container object in Raytracer, let user do it

#ifndef NOISE_H
#define NOISE_H

double perlin(double x, double y, double z);

#endif