Pilot and Designer of Private Rocket Plane Confident By JOHN ANTCZAK     LOS ANGELES (AP) -- The creators of a private rocket plane will go ahead with plans for another launch next week in a quest to claim a multimillion-dollar prize, despite a harrowing flight in which the spacecraft rolled dramatically while hurtling toward the edge of the atmosphere.    Organizers of the \$10 million Ansari X Prize announced without elaboration Thursday night that SpaceShipOne designer Burt Rutan had told them he would go ahead with Monday morning's scheduled flight...