FRANK (LP) US VERSIOIf a series of unfortunate comparisons (like the ones to follow) cause listeners to equate British vocalist Amy Winehouse with Macy Gray, it's only natural. Both come on like a hybrid of Billie Holiday and Lauryn Hill who's had a tipple and then attempted one more late night set at a supper club than they should have. Despite her boozy persona and loose limbed delivery, though, Winehouse is an excellent vocalist possessing both power and subtlety, the