By Denny Dyroff, Entertainment Editor, The Times There is a tasty smörgåsbord of live musical treats in the area over the next few days – rock, blues, Broadway, folk, jazz, alt-rock, singer-songwriter, comedy. Now through July 25, Brandywiners, Ltd. (brandywiners.org) are taking up residence in their summer home at Longwood Gardens (Route 1, Kennett Square, www.longwoodgardens.org) where they...