Commandant Gen. Jim Amos is expected to make a major speech tonight in San Francisco that could provide significant new details about what the future Marine Corps looks like.  Marine officials obviously don’t want to get out front of their commandant, but the speech has been teased to media as focusing on “his vision” for what the service should do next. It will take place at the Marines’ Memorial Club, where Defense Secretary Robert Gates said last August that he was ordering a broad-based review of the Corps’ mission and purpose.  The setting of Amos’ speech is significant. In many…