Annie Dookhan, the former state chemist at the center of a lab scandal which could overturn hundreds of drug convictions, was arrested by state police this morning. Dookhan, 34, was brought out of her Franklin home in handcuffs and put into an unmarked cruiser shortly before noon. She did not speak and kept her head down as she was led down her walkway in front of reporters. Dookhan is charged with two counts of obstruction of justice and falsely pretending to hold a degree from a college or university. She will be arraigned at Boston Municipal Court this afternoon. Dookhan,...