20 months ago wenzelm 2017-10-30 ROOT cleanup: empty 'document_files' means there is no document;
2017-04-20 wenzelm 2017-04-20 more global theories;
2013-03-11 wenzelm 2013-03-11 support for 'chapter' specifications within session ROOT;
2012-08-08 wenzelm 2012-08-08 simplified session specifications: names are taken verbatim and current directory is default;
2012-07-24 wenzelm 2012-07-24 more explicit document = false to reduce warnings; tuned;
2012-07-24 wenzelm 2012-07-24 more session ROOT files;