Over a sea of neon garb and against a backdrop of a just-sunny San Francisco Bay, Chester French got things rolling yesterday at the Treasure Island Music Festival.   The Harvard alums, who have so captivated the likes of Pharrell, Kanye West and Jermaine Dupri, energized the crowd with hits "She Loves Everybody" (which you may recognize from the closing credits of HBO's Entourage) and "The Jimmy Choo's."