If conflict is at the heart of most documentaries, how do you make a film about the nicest, kindest, least conflict-ridden person in the history of television? More specifically, how do you make a doc about Mister Rogers? That was the task that faced Morgan Neville, who won an Oscar for 2013?s ?20 Feet From Stardom,? his film about the struggles faced by a group of backup singers. Two years later, he delivered ?Best of Enemies,? a gripping doc about a series of epic (and vicious) debates between William Buckley Jr. and Gore Vidal. Fred Rogers, the subject of Neville?s new doc, ?Won?t You Be My Neighbor?,? was in many ways the opposite of those guys.