2014-07-23 wenzelm 2014-07-23 clarified module name: facilitate alternative GUI frameworks;
2013-04-04 wenzelm 2013-04-04 separate module "GUI", to keep this out of the way of generic Isabelle_System operations, notably for non-Isabelle/jEdit applications; tuned signature;
2013-03-07 wenzelm 2013-03-07 avoid -Infinity which confuses JFreeChart histogram;
2013-02-22 wenzelm 2013-02-22 updated headers;
2013-01-20 wenzelm 2013-01-20 accomodate scala-2.9.2;
2013-01-18 wenzelm 2013-01-18 use inlined session name as title for charts; tuned signature;
2013-01-18 wenzelm 2013-01-18 charts for future task runtime statistics;