By Ioana Patran and Sam Cage BUCHAREST (Reuters) - Romanian Prime Minister Emil Boc resigned on Monday, giving way to mass protests against IMF-backed austerity measures and joining leaders of other European Union states felled by soaring debts. President Traian Basescu named Boc's justice minister, Catalin Predoiu, to replace him at the head of a government whose popularity is languishing in opinion polls ...