What’s the best way to deal with those especially dark nights of the soul? Get rid of the soul, of course. That’s the premise of French filmmaker Sophie Barthes’ debut feature, a surreal blend of witty comedy and reflective — please excuse the expression — soul searching. Except in this case, the soul-searching isn’t just figurative. A soul has gone missing, and its owner, actor Paul Giamatti (playing actor Paul Giamatti) needs to get…