A Milwaukee police detective suffered minor injuries in a wrong-way crash and an exchange of gunfire early Tuesday morning.  A car going the wrong way on a downtown street hit the squad car and rammed into Stein’s Jewelers and Loan.  The driver of the crashed vehicle jumped out, hopping into a second car and, as it drove away, shots were fired at the police car.  The 43-year-old detective was treated and released.  A 39-year-old detective in the same car wasn’t injured.  Their names weren’t released.