Execution example::

  select Entries --output_columns 'highlight_full(body, "NormalizerAuto", true, "Groonga", "<span class=\\"keyword1\\">", "</span>", "mysql", "<span class=\\"keyword2\\">", "</span>")' --command_version 2
  # [
  #   [
  #     0, 
  #     1407695996.52987, 
  #     0.00151872634887695
  #   ], 
  #   [
  #     [
  #       [
  #         1
  #       ], 
  #       [
  #         [
  #           "highlight_full", 
  #           "null"
  #         ]
  #       ], 
  #       [
  #         "Mroonga is a <span class=\"keyword2\">ＭｙＳＱＬ</span> storage engine based on <span class=\"keyword1\">Groonga</span>. &lt;b&gt;Rroonga&lt;/b&gt; is a Ruby binding of <span class=\"keyword1\">Groonga</span>."
  #       ]
  #     ]
  #   ]
  # ]
