move width & height in the view only, Space is infinite
add algorithm treatment & fix coordinate conversion

    fix conversion from Space coordinate to SpaceView's
    add movement depending on surrounding (add 1 case)
    the neighbors are returned as a bitfield so the comparison towards
        the cases is just an integer check (we use a dict to be faster)
add nbh cases and move them to cases.py

    add a classic test_case
    add test_to_space to convert a test_case to a Space (w/ offset)
add test_cases and move test_to_space in Space

    so we can add multiple test_cases in the same Space
add previous step functionality (Space history)
add obvious nbh case to doc
add two (2,3) test_cases (one fail)