Tunis (AFP) - Tunisia said Sunday it had killed the leader of the jihadists behind the massacre at its national museum, as foreign leaders joined thousands of Tunisians in a march against extremism.Chanting "Tunisia is free! Terrorism out!" the demonstrators marched in a sea of red Tunisian flags to the capital's Bardo Museum, where 21 foreign tourists were killed in the March 18 jihadist shooting rampage."The Tunisian people have proven that they will not give in to terrorism.