rewrote of chart.awk to parametrize width, chart character and justify

Hi keverets,

Thanks for putting these scripts out there. I've been playing with awk lately and your chart.awk was just the stub I needed to visualize Tables of Contents.

                   +++++++++++++++++++++++++++++++++++ 33 1 _The Reach of Explanations_
                                              ++++++++ 8 2 _Closer to Reality_
                ++++++++++++++++++++++++++++++++++++++ 36 3 _The Spark_
                        ++++++++++++++++++++++++++++++ 29 4 _Creation_
                                   +++++++++++++++++++ 18 5 _The Reality of Abstractions_
                              ++++++++++++++++++++++++ 23 6 _The Jump to Universality_
                                     +++++++++++++++++ 16 7 _Artificial Creativity_
                    ++++++++++++++++++++++++++++++++++ 32 8 _A Window on Infinity_
                          ++++++++++++++++++++++++++++ 27 9 _Optimism_
                 +++++++++++++++++++++++++++++++++++++ 35 10 _A Dream of Socrates_
    ++++++++++++++++++++++++++++++++++++++++++++++++++ 47 11 _The Multiverse_
                                ++++++++++++++++++++++ 21 12 _A Physicist's History of Bad Philosophy_
                          ++++++++++++++++++++++++++++ 27 13 _Choices_
                                     +++++++++++++++++ 16 14 _Why are Flowers Beautiful?_
                        ++++++++++++++++++++++++++++++ 29 15 _The Evolution of Culture_
                                 +++++++++++++++++++++ 20 16 _The Evolution of Creativity_
                            ++++++++++++++++++++++++++ 25 17 _Unsustainable_
                                    ++++++++++++++++++ 17 18 _The Beginning_