By Tarek Amara TUNIS (Reuters) – Since taking a lead role in criticizing Tunisia’s increasingly powerful president, prominent journalist Mohamed Boughalleb has been out of work, part of what he and press rights activists believe is a quiet policy to chill dissent. Boughalleb was well-known for his scathing critiques, spearing figures across the political spectrum on his radio show as free speech blossomed after Tunisia’s 2011 revolution. But as his show closed and job opportunities suddenly dried up this summer, he started to fear that Tunisia’s place as a rare beacon of press rights in the re…