By Axel Bugge SINTRA, Portugal (Reuters) - Disillusion with Portugal's main parties, both battered by association with the country's deep economic crisis and international bailout, is translating into a surge in independent candidates for Sunday's local elections. While government austerity measures - a condition of the bailout - have sparked periodic protests and strikes, the protests haven't turned violent, as in Greece, nor have voters turned to extremist political parties to vent their anger. Their outlet, instead, appears to be the unaligned. ...