There was something of a three-ring freak show over at the National Press Club yesterday, where convicted felon Larry Sinclair appeared at a press conference attended by a group of gawking international reporters. For those of you who don’t follow crackpot theories about major national political figures, here’s the basic story: Larry Sinclair, a professional weirdo who has been in the past successfully prosecuted for crimes involving lying, like forgery and bad checks, has…