No ''Sunny'' style arson here, on Whole New You. Now that she's on the mommy track, Shawn Colvin writes about the impossibility of leaving, much less returning, with a torch. Not that she's always happy about hunkering down: The opening ''Matter of Minutes'' nicely delineates that old ''can't stay, can't split'' dilemma. The more ebullient title song deals with the unlikeliness of reinvention -- not really a problem for someone as likably set in her ways as this folk rock ma.