Elizabeth Wagmeister Senior CorrespondentHot off the heels of a major victory for pop star Britney Spears, Hollywood litigator Mathew Rosengart is stepping into yet another guardianship case for a high-profile individual: iconic artist Peter Max, whose family is fighting to get him out of the court-ordered arrangement.Max, the German American artist known for his use of bright colors, psychedelic style and pop art that often includes American symbolism, is under a guardianship that his family