(Reuters) - Venezuelan authorities have jailed a former state governor and presidential candidate who accused President Hugo Chavez's government of links to subversive groups in Latin America. The detention of Oswaldo Alvarez Paz, a veteran with the opposition COPEI party but not one of Chavez's most prominent foes, will fuel criticism that the Venezuelan leader is taking his nation down an increasingly dictatorial route. Alvarez joins a list of several dozen Chavez opponents now in jail, living in exile or facing probes in the South American oil-producing country. With the political atmosphere heating up before legislative elections in September --...