Three Floors” opened with a high-profile belly flop, festival-stalwart Nanni Moretti returns to Cannes with “A Brighter Tomorrow,” a comeback of sorts that also airs a list of grievances and could serve – should need arise – as a closing statement.Not that it likely will. Funny and endearing in some places, and typically grumpy and old-fashioned in others, “A Brighter Tomorrow” should, at very least, keep Moretti far from director’s jail for years to come.