R&B star Rihanna this week filed a lawsuit naming her former accountants, seeking millions of dollars in damages for shoddy bookkeeping, bad advice and failure to direct her with regards to an ongoing IRS audit.  The singer filed the lawsuit Thursday in a Manhattan federal court, naming Berdon LLP and two accountants who work for the firm.  Rihanna dismissed Berdon in September 2010, after the firm had handled her business dealings since she was 16.