def initialize(options = {})
      @grid_lines = @headings = @horizontal_centered = @vertical_centered = false
      set(options)
    end
Creates a new PrintOptions object
@option options [Boolean] grid_lines Whether grid lines should be printed
@option options [Boolean] headings Whether row and column headings should be printed
@option options [Boolean] horizontal_centered Whether the content should be centered horizontally
@option options [Boolean] vertical_centered  Whether the content should be centered vertically