There they were, on stage Sunday night at the 49th annual Monterey Jazz Festival, three all-time great jazz pianists Oscar Peterson, Dave Brubeck and Hank Jones being honored before a sell-out crowd. Besides celebrating established jazz giants, the three-day festival presented some of the world’s best young musicians, playing mainstream as well as smooth, blues and cutting-edge jazz in four venues on the Monterey fairgrounds. More good news this year--the MJF set an all-time record of 43,000,