first code commit with general structure

    main view contains a canevas
    that can view the scene, move around, zoom, etc
    the canevas contains a "stair model"
    that we will largely use to compute stairs projections, tests, etc...
    geom and camera were widely taken from this project, name mentioned in authors
    http://profs.etsmtl.ca/mmcguffin/code/python/example-3D_Python-Qt-OpenGL/