2012-11-26 ago more general sendback properties;
2012-11-25 ago Isabelle-specific implementation of quasi-abstract markup elements -- back to module arrangement before d83797ef0d2d;
2012-09-27 ago removed obsolete org.w3c.dom operations;
2011-11-29 ago clarified Time vs. Timing;
2011-11-29 ago separate compilation of PIDE vs. Pure sources, which enables independent Scala library;
2011-11-29 ago rearranged files;