Wynn Resorts and Massachusetts gambling regulators finalized the license Wednesday for a $1.6 billion casino outside Boston.Wynn brings a track record of success in competitive gambling jurisdictions, including Las Vegas and Asia, said James McHugh, acting commissioner of the Massachusetts Gaming Commission.It's also "taking on an enormous challenge" in redeveloping a heavily polluted former chemical plant site along the Mystic River in Everett, he said.