Celtics draft picks — and, perhaps with a little luck and hard work, future stars — Jared Sullinger, Fab Melo, and Kris Joseph joined team owners Wyc Grousbeck and Steve Pagliuca, and president of basketball ops Danny Ainge and checked out the newly renovated library and multipurpose room at the Jackson Mann Educational Complex in Allston. The new space was made possible in part by the Celtics’ Shamrock Foundation.