[PyMOL] `selection` argument in load_traj

[brisvag <br...@gm...>]

Hi Thomas,

I see! Is it supposed to work with other formats too? Or at least, is
it planned to be expanded? I'm trying to switch to PyMOL to view
GROMACS `.xtc` trajectories, and this feature would be a great
addition.

Cheers,
Lorenzo