Mexico's presidential election was too close to call Sunday with voters bitterly divided between a leftist offering himself as a savior to the poor and a conservative warning his rival's free-spending proposals threaten the economy. Electoral officials were conducting a quick count of the votes, and were hoping to declare a winner later Sunday. But they warned that they would hold off — perhaps for days — if neither candidate had a large enough advantage.Mexico's two main television networks did not release the results of their exit polls, saying