By Denny Dyroff, Staff Writer, The Times Ottmar Liebert A project by Ottmar Liebert can be as international as a United Nations committee meeting. Liebert, who will be performing with his band Luna Negra on May 24 at the Sellersville Theater (24 West Temple Avenue, Sellersville, 215-257-5808, www.st94.com), has been multi-national since he was born. The talented musician grew up in Köln, Germany...