2010-01-04 ago discontinued special HOL_USEDIR_OPTIONS;
2009-11-09 ago switched some isatest sessions to official Poly/ML 5.3.0;
2009-10-30 ago back to polyml-svn -- performance impact is minimal, slowdown was caused by accumulated cruft of long-running Mac OS;
2009-10-25 ago more uniform ISABELLE_USEDIR_OPTIONS;
2009-10-25 ago switch to polyml-5.2.1 to see if it impacts performance;
2009-07-30 ago ISABELLE_USEDIR_OPTIONS: -q 2 by default;
2009-07-25 ago internal session timing;
2009-07-23 ago tuned ML_OPTIONS;
2009-07-22 ago less ambitious settings;
2009-07-20 ago replaced usedir option -Q by more fine-grained -q;
2009-06-16 ago less ambitious ML_OPTIONS;
2009-06-13 ago proper ISABELLE_HOME_USER;
2009-06-12 ago more isatests;