NEW YORK (Reuters) - As the founder of the groundbreaking rap group Public Enemy, Chuck D blended music and politics in hits like the 1989 anthem "Fight the Power." Now he's "rapping" about politics on Air America Radio, a new and unabashedly liberal radio network. His show "Unfiltered," which began this month in five markets, teams the rapper with comedian Lizz Winstead and radio veteran Rachel Maddow in a three-hour format that promises to examine the state of U.S. politics and culture. The 43-year-old musician is promising to put his unique stamp on the show, using it to revitalize black...