def [](index)
      raise Grim::PageNotFound unless index >= 0 && index < count
      Grim::Page.new(self, index, pdftotext_path: @pdftotext_path)
    end
def [](index)
      raise Grim::PageNotFound unless index >= 0 && index < count
      Grim::Page.new(self, index, pdftotext_path: @pdftotext_path)
    end
Creates an instance Grim::Page for the index passed in.

 index - accepts Integer for position in array

 For example:

   pdf[4]  # returns 5th page

 Returns an instance of Grim::Page.