clarified internal data representation, following push/pop model of Scala version;

tuned names;

more accurate formatting of open_block: markup only, without affecting layout (e.g. via force_next); tuned signature;

tuned: more uniform;

proper treatment of XML.Wrapped_Elem as open_block (amending 7cacedbddba7, but this case is presently unused);

tuned;

unused;

tuned signature;

tuned: more uniform;

tuned: more uniform;

clarified data representation: less redundancy;

tuned;

minor performance tuning;

clarified signature: more direct indent_markup; minor performance tuning: bypass "ind" buffer when unused;

more LaTeX markup;

Backed out changeset 0ca0a47235e5 (produced Code check failed for Haskell?)

tuned

merged

merged

merged

tuned slow proof

merged

proper bullet symbols for GUI text -- in contrast to Isabelle \<bullet> 0x002219;

tuned: more direct GUI painting via HTML;

tuned generated output: more standard operations;

tuned GUI output: more uniform;

minor performance tuning;

tuned generated output: more standard operations;

clarified signature: more operations;

more accurate treatment of plain text (amending eede0cf38a63);