title: Tabbing in Deoplete is Backward
body: <p>When I trigger the autocomplete menu in Deoplete, the tab key's behavior is backward. For example, let's say I pop up an autocompletion drop down.\</p>
  
  <p><a href="https://i.stack.imgur.com/IHXuz.png" rel="noreferrer"><img src="https://i.stack.imgur.com/IHXuz.png" alt="Deoplete drop down"></a></p>
  
  <p>When I hit the tab key, I would expect Neovim to select the first item in the list. Instead, it selects the last.</p>
  
  <p><a href="https://i.stack.imgur.com/rFEby.png" rel="noreferrer"><img src="https://i.stack.imgur.com/rFEby.png" alt="Deoplete drop down tab"></a></p>
  
  <p>I'm not sure if this behavior is specific to Deoplete or is a generic issue with Neovim.</p>