NEW ORLEANS -- Times-Picayune music writer Keith Spera writes, "They didn't intend for it to be this big. Thanks to good will, good fortune and a goodly investment of cash, producers of the New Orleans Jazz and Heritage Festival presented by Shell have unveiled perhaps the deepest talent pool in the festival's 39-year history. Stevie Wonder, Billy Joel, Sheryl Crow, Keyshia Cole, Robert Plant with Alison Krauss, and the previously announced Tim McGraw are all headed to the Fai