by John Mulvey Sky Blue Sky 2007-03-05 16:35:01 Jeff Tweedy has always been a perverse bugger. When Wilco became the toast of the Americana classes, Tweedy did everything in his considerable power to disassociate himself from the scene. He made the two greatest albums of his career, "Yankee Hotel Foxtrot" and "A Ghost Is Born", and saw his band hailed as so adventurous as to be virtually avant-garde. Clearly, though, being stereotyped as a radical is starting to get on his nerves. Initially "Sky Blue Sky", the new Wilco album, sounds like a conscious attempt to get rid of all those Soni