proper support for recursive ML debugging;

tuned -- avoid recoding properties;

removed old proof method "default";

clean message more thoroughly;

clarified modules; removed unsed exn_id;

avoid interference with running PIDE protocol;

proper signature for structure; tuned;

tuned signature; proper signature for structure;

proper output of markup, e.g. relevant for nested ML as used in Pure/System/bash.ML;

support ROOT0.ML as well -- independently of ROOT.ML;

flags as in 'ML' command;

shared output primitives of physical/virtual Pure;

shared thread position for physical/virtual Pure;

prefer Synchronized.var;

tuned signature;

virtual Pure is single-threaded to avoid confusion with multiple thread farms etc.;

tuned signature;

tuned signature -- closer to Exn.Interrupt.expose in Scala;

clarified bootstrap;

clarified context; avoid Unsynchronized.ref;

old;

ensure globally unique counter results;

tuned;

clarified modules;

backout 930a30c1a9af: leads to odd effect of command-line options becoming persistent preferences;

eliminated ancient TTY-based Tactical.tracify and related global references;

updated according to 705d4c4003ea;

option "-o" for "isabelle jedit";

eliminated unused simproc identifier;

section headings for ROOT.ML;

back to dynamic conditional compilation (reverting 4764473c9b8d) via recursive ML name space;

explicit handling of recursive ML name space, e.g. relevant for ML_Bootstrap; handle bootstrap signatures as well;