WOLE Soyinka knows what it is to be trampled on and how it feels to be oppressed. Soyinka, the Nigerian who won the Nobel Prize for literature in 1986, is now 74. When he was 31, his government imprisoned him for three months, and two years later, when he was director of the Drama School at Ibadan University, he was arrested because his writings were considered to support the Biafran separatist movement. He was imprisoned for a year, including in