Feature: “Printer friendly” and “Monochrome” options in monthly log and historical chart pages

Added ``Printer friendly'' and ``Monochrome'' checkboxes to the monthly log page. These set ``{\tt print}'' and ``{\tt mono}'' CGI arguments which are propagated to navigation links and the embedded chart. These choose CSS classes which re-format the monthly log for a printer and, if set, monochrome output. In printer friendly mode, the monthly log table is a non-editable static table with collapsed borders.

Added ``Printer friendly'' and ``Monochrome'' checkboxes to the Chart Workshop and passed them on to {\tt history::drawChart} to apply those modes to the historical chart.