Power Trip, Prong, Weekend Nachos, Hirax, Jeffrey Nothing, Casket Robbery, and Polkadot Cadaver have been added to next year’s Milwaukee Metal Fest. That event will take place at The Rave/Eagles Ballroom in Milwaukee, WI on June 5-7. A pre-party is also being scheduled for June 4. Previously announced acts include: Killswitch Engage, Acid Bath, Iron…