Improve plot comparison scripts. * compare_plot_demos.m: pass toolkits{} to html_compare_plot_demos. Give instructions for toolkit matlab. Fix whitespace issue. * dump_demos.m: fix typo in default dir. Consistently use dump_plot_demos.m for main worker script. Create diary and error messages for inclusion in html page. Set random seed for better comparison. * html_plot_demos_template.html: Allow variable toolkits (removed hard-coded gnuplot, matlab, fltk sequence). Fix some whitespace issues. * html_compare_plot_demos.m: Rewrite docstring. The instructions are no longer needed because compare_plot_demos handles them. Add "toolkits" and column_width param. Dynamically add toolkits in html, add diary.log link.

header = '{date|shortdate}  {author|person}  <{author|email}>\n\n'
changeset = '\t{desc|tabindent|strip}\n\n\tFiles: {files|stringify|fill68|tabindent|strip}\n\n'