Lil Wayne was granted a breakthrough in his legal battle over unpaid royalties this week. A judge has ordered Birdman to open up his books to provide a record of what a $100 million advance Cash Money received from Universal Music Group, has gone towards. Disputed in the case is $70 million of those $100 million dollars, which Wayne was supposed to get a split of for marketing and recording expenses, in addition to the royalties he claims to have never received. Lil Wayne’s legal team recently demanded a more comprehensive money trial, after his attorneys dismissed the 22,015 pages of legal documents provided by Birdman’s accountant as useless. Lawyers…