MIAMI (Reuters) - Jack Abramoff, a disgraced lobbyist at the heart of a Washington influence-peddling scandal that has rattled top Republicans, was sentenced to nearly six years in prison on Wednesday for fraud in the purchase of a Florida casino cruise line. Abramoff, who is cooperating in a federal investigation into whether Washington politicians gave his clients favorable treatment in exchange for campaign contributions, Super Bowl tickets and other illegal gifts, was sentenced to 5 years and 10 months in prison. Abramoff, along with co-defendant Adam Kidan, was ordered to pay $21.7 million in restitution. Kidan was also sentenced to...