src/Pure/GUI/system_dialog.scala
2014-07-23 ago clarified module name: facilitate alternative GUI frameworks;
2014-04-22 ago avoid "Adaptation of argument list by inserting ()" -- deprecated in scala-2.11.0;
2013-12-09 ago alternative hires icon;
2013-11-09 ago adjust modules for Admin/build jars_test;
2013-09-24 ago more quasi-generic PIDE modules (NB: Swing/JFX needs to be kept separate from non-GUI material);
2013-09-22 ago clarified location of GUI modules (which depend on Swing of JFX);