The Portland School Board on Tuesday night approved a two-year contract with the teachers union that includes a 2 percent cost-of-living increase and increases class time for students and professional development time for teachers. Also Tuesday, the school superintendent released the latest test and performance data for the district, showing mixed results. Starting in the 2015-16 school year, students will have an additional 20 minutes of class a day, creating a 6½-hour school day.