Summary
- merged;
- updated to jedit_build-20190717: support more brackets;
- updated to isabelle_fonts-20190717;
- redundant;
- tuned;
- added \<llangle>, \<rrangle>; discontinued special rendering for old {* *};
- tuned doc isar-ref;
- added \<bbar>;
- added \<sqdot>;
- fixed renaming issues
- merged
- a few new lemmas and a bit of tidying