add_bracket_comparisons
                        Create comparison specification for vbracket
draw_legend_with_brackets
                        Create a custom legend with vertical brackets
ggplot_add.vbracket_legend
                        Add vbracket legend to ggplot
ggsave_vbracket         Save a ggplot with vbracket legend
legend_bracket          Add legend with brackets to a ggplot object
p_to_symbol             Get standard significance symbols from p-values
plot_with_custom_legend
                        Add custom legend with brackets to a ggplot
print.gg                Print method for ggplot objects with vbracket
                        legend
