By Denny Dyroff, Entertainment Editor, The Times Imagine turning 90 and still be bursting with energy. Well, that’s what is happening with the Chester County Old Fiddlers’ Picnic (Hibernia County Park, off Route 340, Wagontown, 610-383-2812, http://dsf.chesco.org/ccparks). The lively annual event, which is scheduled for August 11, is celebrating its 90th anniversary this year. Known originally...