added \<llangle>, \<rrangle>; discontinued special rendering for old {* *};
added \<bbar>;
added \<sqdot>;
more mathematical glyphs from Isabelle2009-1/lib/fonts/IsabelleMono.sfd (still unused);
clarified names; --HG-- rename : Admin/isabelle_fonts/IsabelleText.sfd => Admin/isabelle_fonts/IsabelleSymbols.sfd rename : Admin/isabelle_fonts/IsabelleTextBold.sfd => Admin/isabelle_fonts/IsabelleSymbolsBold.sfd