2010-01-04 ago discontinued special HOL_USEDIR_OPTIONS;
2009-11-09 ago switched some isatest sessions to official Poly/ML 5.3.0;
2009-05-31 ago uniform treatment of shellscript mode;
2008-06-06 ago switched to Poly/ML 5.2;
2008-03-24 ago replaced obsolete /usr/proj by /home;
2008-03-06 ago removed obsolete THIS_IS_ISABELLE_BUILD feature;
2007-12-05 ago switch poly to 5.1, removed -e flag from most sessions
2007-03-05 ago additional settings for isatest runs on various platforms