By DENNY DYROFF, Staff Writer, The Times   It’s always a good trait to have the ability to laugh at yourself. This weekend, Philadelphia will have the opportunity to laugh at itself when Chicago’s legendary sketch and improv comedy theater Second City performs three shows on November 13 and 14  the Kimmel Center  (Broad and Spruce streets, Philadelphia, 215-731-3333, www.kimmelcenter.org). The...