Let it never be said that Paramount emperor Brad Grey is not a beneficent ruler: To celebrate the success of partner DreamWorks Animation's Shrek the Third, he's setting his subjects free a day early for the Memorial Day weekend, an act of generosity that should remind everyone on the Melrose lot that the Paramount Pictures logo can be found somewhere on the one-sheet of the latest. record-breaking installment of the previously established DW mega-franchise. Grey's e-mail to the company follows, which stops just short of promising all of his underlings an all-expenses-paid week in Cancun should the opening weekend performance of upcoming co-production Transformers bring still more glory to the Paramount name: