misc tuning and modernization;

merged

clarified signature;

clarified signature: more general types;

afford redundant whitespace for improved readability;

avoid context-sensitive simp rules whose context-free form (image_comp) is not simp by default

tuned signature;

clarified signature -- allow more re-use;

concrete predicates from "Dublin Core";

clarified signature; suppress already loaded theories;

tuned signature;

tuned document;