2012/07/26 Headlines: Syrian Troops Continue Siege of Aleppo; U.S. Says Record Drought Will Drive Up Food Prices Next Year; Colorado Shooting Suspect Detailed Massacre Plans in Unopened Letter; Obama Vows to Tackle Gun Violence in Louisiana Speech; U.S. Urged to Support 1st Global Arms Control Treaty; 24 Arrested in Anaheim Police Shooting Protests; Geithner Faces Questions over Response to Libor; Coalition of Immokalee Workers Targets Chipotle in Push for Humane Farmworker Conditions; Report: Skype Gives Police Access to User Info, Chats; Anarchist Accused in Cleveland Bomb Plot Agrees to Testify Against Others;$