On paper, this tasteful Pennsylvania quartet has it all: a distinctive singer in keyboardist Karen Peris, well-crafted arty folk-pop songs with intelligent, substantial lyrics, delicately skillful musicianship. On its self-titled debut, however, the Innocence Mission sounds like a once-sprightly group that’s had the life washed out of it. Lacking the resonant eccentricities of 10,000 Maniacs or the artistic depth of the Cocteau Twins, this polished veneer of adult refinement is much easier to admire than enjoy.