Fans have been eagerly anticipating aMEAN GIRLS musical, which has been in development for several years. At the 10th Anniversary celebration of the comedy film, Fey and her husband, composer Jeff Richmond, said they were hoping MEAN GIRLS will hit the stage in time for -- or ahead of -- its 15th anniversary, which will be in 2019.It looks like that might happen, because a new, verified Mean Girls Twitter account has…