Merge pull request #2 from merlinND/camera

Camera basics
Move render-related files to their own subdirectory
Proper Image class
Write Image resulting from render
Ray throwing stub
Use intersections when throwing rays
Compute Cube boundaries
Cube intersection algorithm [not tested]
Merge pull request #3 from merlinND/renderer

Basis for image rendering by casting rays
Merge branch 'master' into geometry
Fix casting problem
Appreciate perspective
Merge pull request #4 from merlinND/geometry

Basic cube intersection algorithm
Add current render example
Recursion stopping criterion
Choose the test scene's background color at random
Algorithm prep for color computation
Intersection stub
Add some TODO
Compute intersection with Cube