WATERLOO — It’s been nearly 33 years since the governor joined a crowd of city leaders to celebrate a groundbreaking for Waterloo Greyhound Park.Many others showed up Wednesday to cheer as demolition contractors began tearing down the dilapidated dog track, which had turned into a community eyesore as its future languished in the courts.“We’re excited for this day to finally come,” said Harold Youngblut, president of Deer Creek Development.