CAMBRIDGE-Embodying the everlasting respiration of culture and counterculture, Bang on a Can, the new-music collective founded by composers Michael Gordon, David Lang, and Julia Wolfe, has gone from loft-concert outsiders to new-music establishment mainstays. In their 25th season-and in the midst of a three-year residency at MIT, academic home of Evan Ziporyn, a member of the affiliated Bang on a Can All-Stars ensemble-the group brought two recent pieces to MIT’s Kresge Auditorium on Saturday. Their means remain distinctive, a sometimes clashing cross between minimalism’s disciplined patterns and post-minimalist rock and populist energies. But the ends have evolved in encyclopedic directions.