Years in the planning stages, the new New Brunswick Performing Arts Center, situated next to the State Theatre on Livingston Avenue, is at long last ready to open this fall. Interestingly, the State Theater is not formally part of this complex because it’s already been renovated several times, but given its location next door, the State Theater and New Brunswick PAC will feed off one another, as arts-minded patrons see signs and hear conversations about upcoming productions at both venues.