WASHINGTON - Shoppers posted an optimistic message about the US economy as the Conference Board reported its March consumer index rose 4.5 points, to 107.2, the highest level since May 2002. Analysts had expected a reading of 102.
   The outlook for the labor market was also more upbeat. Those expecting fewer jobs to become available in the coming months decreased to 16.6% from 19.9% in February, while those expecting more jobs edged up to 13.9% from 13.4%.