Meat and potatoes rock 'n' roll was on the menu Saturday night at the Blue Hills Bank Pavilion in Boston, where Needtobreathe, Switchfoot and two other acts provided about four hours of music for an all ages crowd of about 4,300 fans.If there might have been a dollop of Christian outreach included, it was mostly pretty subtle and between the lines, but may have accounted for the unusual number of young folks with their parents in the crowd.