HARARE (Reuters) - Zimbabwe s main opposition said on Thursday it wanted incoming president Emmerson Mnangagwa to dismantle all pillars of repression that helped sustain Robert Mugabe s 37 years in power. In its first official comments since Mugabe resigned on Tuesday, the MDC said it was cautiously optimistic that a Mnangagwa presidency would not  mimic and replicate the evil, corrupt, decadent and incompetent Mugabe regime.  