Also: The 80s make an amazing comeback at The Keswick By Denny Dyroff, Staff Writer, The Times The Quebec-based progressive folk group Le Vent du Nord will perform a free show for Longwoof Gardens members, Friday. By far, one of the most interesting musical events to hit the area this summer will take place on August 21 at Longwood Gardens (Route 1, Kennett Square, 610-388-1000, www.longwoodgardens.org). Jackie Evancho,...