KUALA LUMPUR – Tun Dr Mahathir Mohamad still has bitter feelings for the former prime minister Mohammad Najib bin Tun Haji Abdul Razak and what he did to his former party – UMNO. Dr Mahathir blamed Najib for destroying the Malay party he once led. He indicated that the differences between him and Najib, whom he once mentored, were irreconcilable. …