Add new capabilities to Neovim buffer running R.
Better emulation of Console capabilities:
  - Autocompletion: <C-x><C-o> and <C-x><C-a>
  - Cicle through history: <Up> and <Down>
  - Complete previous command: <C-h>
  - See history of commands:  :Rhistory
  - Stop R:  <C-c> or :RStop