 CBS NEWS SPECIAL REPORT. FORMER PRESIDENT DONALD TRUMP ARRIVED IN MILWAUKEE FOR TODAY'S START OF THE REPUBLICAN NATIONAL CONVENTION, PROMISING AN ENTIRELY DIFFERENT SPEECH THAN HE'D PLANNED, AFTER A BULLET GRAZED HIS EAR, COMING WITHIN MILLIMETERS OF KILLING HIM. OFFICIALS SAY 20-YEAR-OLD GUNMAN THOMAS MATTHEW CROOKS LIVED NEAR THE RALLY IN BUTLER, PENNSYLVANIA. CBS'S MEG OLIVER.