Fix chomp and read_lines

Implements the POLA behavior of reading lines.

Note: it seems that the interpreter behave strangely. However, things seems fine when combined with #932.
Therefore, I might have to wait that #932 is merged before integrating this one.

Close #974 and close #975 (see them for details)
C’est une convention assez répendue de mettre les noms Unicode en majuscules. Moi, ce qui me choque le plus, c’est le `&`.