The Occupy Wall Street movement’s dark underbelly is on full display in an explosive new documentary set for release later this month. "Occupy Unmasked," produced by the non-profit group Citizens United and the late Andrew Breitbart, in one of his last projects before his death last March, examines the movement and its possible links to organized labor and leftist groups. Its premiere in theaters on Sept. 21 follows the release of the documentary "2016: Obama's America," providing more cinematic fodder for the president’s critics ahead of the Nov. 6 election. FoxNews.com was given an advanced screening of the 70-plus minute...