time funs: +1 instead of 1+

minor performance tuning;

clarified signature: more comprehensive operations;

clarified signature: more explicit types;

clarified signature: emphasize physical db files;

tuned: afford untyped/unscoped update;

clarified signature: avoid ill-defined type java.net.URL;

unused;

tuned: afford untyped/unscoped update;

more robust default: Scala imposes explicit "threads" value on ML, both the Poly/ML RTS and Isabelle/ML;

clarified signature: more explicit types/scopes;

tuned names;

tuned;

tuned documentation;

more robust: disallow empty clusters, so "isabelle build -H" really means cluster build;

clarified modules: centralize default policy;

more explicit types --- fewer warnings in IntelliJ IDEA;

tuned: avoid shadowing of names;

clarified default "isabelle build -j0 -H";

tuned whitespace;

clarifier worker vs. master, which may coincide for local build;

clarified signature: more standard defaults;

clarified signature;

clarified signature;

tuned;

prefer static object, while class is required for "services";

clarified signature: prefer default;

merged

tuned;

more robust: check subclasses as well;