For the last quarter century, college students from Wisconsin have gotten on a plane, landed in Scotland and spent a semester or year together in the most splendid of dormitories: an 18th century castle in Dalkeith, a village six miles from Edinburgh. Starting soon, the castle will get more diverse. Wisconsin students in Scotland will be joined by students from Virginia State University, a historically black college in the shadow of Fort Lee, a key battleground in the Civil War.