So far the production of 'X-Men: Days of the Future Past' has been marked by returns. Bryan Singer is returning to the franchise to direct for the first time since 2003's 'X2.' Also, we know that Patrick Stewart and Ian McKellen are coming back to play the future versions of Professor X and Magneto. Not only that, but Hugh Jackman will purportedly also be reprising his role as Wolverine in the up…