FALLS CHURCH, VA.- While Washington, D.C., has long been a hive for international activity, the districts suburb of Falls Church, Va., is where the fine art of many nations will be showcased on Saturday, March 5. Thats when Quinns Auction Galleries will host its 500-lot International Furnishings, Fine & Decorative Arts sale. The selection of fine art and furniture in this auction is, by far, the finest and most diverse we have ever offered, said Quinns VP Communications & Marketing Matthew Quinn. The main consignor is a Washington-area physician who has very refined taste and a preference for English furniture and Continental paintings. A premier piece from the doctors consignment is an 1850 English walnut with marquetry tilt-top table measuring