Boeing workers are voting on a new labor contract on Thursday, setting up the potential for a crippling strike if staff members decide to reject the deal just as the plane-maker is trying to ramp up its production.The tentative agreement that the International Association of Machinists and Aerospace Workers and the company unveiled on Sunday included 25% wage increases and other improvements to health-care and retirement benefits. Boeing also committed to build its next aircraft in the Seattle area.The vote ...