Spain's ruling PP extends poll lead but Socialists rise

By Julien Toyer MADRID (Reuters) - Spain's ruling People's Party is on course to win the most votes in a national election in December, a poll showed on Thursday, but the rise of the opposition Socialists and new party Ciudadanos has increased the possibility of a center-left government. The closely-watched survey, released quarterly by the Sociological Research Centre (CIS), also showed that leftist Podemos, which ranked a close second earlier this year and raised the prospect of a Greek-style