It wasn’t just the Avatar movies that received release dates today. 20th Century Fox made a number of changes and additions to their future 2017-2018 lineup. First, the sequel to Fox/Marvel’s $783M 2016 hit, Deadpool 2 will open on June 1 next year and it’s the only tentpole slotted there currently. Pic was previously listed on the calendar as untitled Fox/Marvel movie on June 29. X-Men spinoff New Mutants fills another untitled Marvel slot on Fox’s calendar, moving from…