A century after his birth in Harlem, the writer and activist James Baldwin is being celebrated for his visionary work, and for the many facets of his personality – Black, gay, playwright, essayist, New Yorker, expatriate – that transformed him into an iconic figure in the civil rights movement, even beyond his death in 1987 at age 63. “Sunday Morning” contributor Kelefa Sanneh looks back at the author of such noted works as “Notes of a Native Son,” “The Fire Next Time,” and “Giovanni’s Room.”