While Cape Verde's best known singer is Cesaria Evora, Lura born and raised in Lisbon's emigre community- is introducing uder-exposed Cape Verdean styles to U.S. and European audiences.  Lura will sing selections from her forthcoming debut "Di Kropu Ku Alma" 8p.m. Sunday at S.O.B's, 204 Varick St, New York. $25. Call (212)