Where a defendant in a postconviction petition seeks to review an issue that is barred due to res judicata because of new evidence, that evidence must be conclusive, material, discovered since the trial and of such a character that it could not have been discovered with reasonable diligence before trial.The 1st District Appellate Court affirmed the decision of Cook County Associate Judge Lauren Gottainer-Edidin.On Feb. 24, 2003, David Kraybill rang the bell at the home of Joel Cacharelis, his childhood friend, and …