change square case mvt and end detection

    don't go in the corner, go straight
    end detection is done by comparing next surrounding w/ previous one
    rotated by 270° instead of 180
chg mvt of square case
add lemma 1 and 2

    1. bb not inflating
    2. a single robot collapses
ignore all in doc/ except pdf and tex
move Tk window making in a display_space()
update algo to consider the change in square case
update algo : add check for 1.2.4 and 1.3.5

    and remove continue after checking termination
add vertical symetric cases and update algo accordingly
add an argument to \spacee fct: size of the grid
don't ignore pdf and tex files in doc/
move proof to proof.tex and add proof stuffs

    add proof for a single robot on topmost row w/ graph
    add 2 graphs for the topleft robot on the topmost row
add proof code even if it's a draft