New York’s new teacher-evaluation system–designed to rate them based in part on student scores in reading and math–is in jeopardy after the state teachers union filed a lawsuit challenging its legality, reports the New York Post. The lawsuit, filed yesterday in State Supreme Court in Albany, signals a major rift in cooperation between the union and the state Education Department–which had worked together to win nearly $700 million in federal funds through the Race to the Top competition…