In 2007 she wouldn’t write us a love song, but now the plucky piano popster is back with a disc full of ’em. On Kaleidoscope Heart, sometimes, as in the airless ”Breathe Again,” all that earnest yearning can make you feel like you’ve been sentenced to life at Lilith Fair. But when producer Neal Avron piles on the theater-kid sparkle — love those strings in ”Uncharted”! — Bareilles sounds like a friendlier Fiona Apple. B?