By Denny Dyroff, Entertainment Editor, The Times New Reveille When Shawn James’ fans make the trip northward to Upper Bucks County to catch his show on August 10 The Sellersville Theater (24 West Temple Avenue, Sellersville, 215-257-5808, www.st94.com), they would be well advised to get to the comfy theater early enough to hear the opening band’s set. Performing the role of lid-lifter will be...