cell vectors are written wrong in .gro files

The cell vectors are written wrongly in .gro files I think.

The relevant part is in the end of ase/io/gromacs.py

What should be written is v1(x) v2(y) v3(z) v1(y) v1(z) v2(x) v2(z) v3(x) v3(y)

What seems to be written is v1(x) v2(y) v3(z) v2(x) v3(x) v1(y) v3(y) v1(z) v2(z)