Load unknown library.
  
    $ antigen-use unknown
    Antigen currently supports only following libraries:
     * oh-my-zsh
     * prezto
    [1]
  
  # Fixme: loading prezto or oh-my-zsh library breaks all the tests.
  # 
  # Load prezto library.
  # 
  #   $ antigen-use prezto &> /dev/null
  #   $ antigen-bundle git &> /dev/null
  # 
  # Load oh-my-zsh library.
  #  
  #   $ antigen-use oh-my-zsh &> /dev/null
  #   $ antigen-bundle git &> /dev/null