fixed problem with time_fun in locales

more Java heap space for the sake of Isabelle/AFP cluster build stability, but this is better changed elsewhere; enforce rebuild of Isabelle/ML;

merged

build_progress with percentage;

clarified signature: prefer static percentage;

more informative Progress.Nodes_Status;

more informative Command_Span.Theory_Span;

tuned;

more accurate theory timing, based on sum of command timings; remove obsolete protocol message;

support for detailed build progress;

proper symbolic_path for nodes_domain;

tuned;

tuned signature;

clarified signature;