Keri Hilson is prepackaged but entertaining at WPGC���s birthday concert at 9:30

than a half-dozen acts both recent and vintage, but it was the crazy-prolific R&B hitmaker (and newly crowned Avon cosmetics spokesmodel) Keri Hilson who got to bat cleanup. Her hits-dense, rigidly paced 35-minute set culminated in Pretty Girl Rock, a...