The derogatory title of his searing documentary film, “A Little Black Man from Congo” isn’t what South African filmmaker Tshililo waha Muzila came up with by himself. It’s what he discovered that “they” are called in Spain: The irregular migrants, asylum seekers, refugees and undocumented migrants, precariously – and often fatally – trying to reach Europe in anything afloat, desperate in search of a better life. In Spanish, the term is “Negrito Del Congo.” His evocative in competition