fixed the scanline order (one row at a time instead of one column at a time) - this...

fixed the scanline order (one row at a time instead of one column at a time) - this magically fixed the corrupted image if requested dimenstions were not square (raytracer:go(16, 12, "file.ppm") for example)
commented out some debug messages
updated the scene and scene test

git-svn-id: http://svn.plouj.com/repos/eraytracer@12 b8c14938-b733-429d-887c-d66ed1f8cd15