Here is a summary of the changes in migrating from the old SML/NJ Library
(version 0.9) to the SML/NJ Util Library:

    - eliminate weak types in signatures.

    - name changes to track SML Basis conventions.
	- change names, argument order of iteration combinators
	- use MONO_XXX/XXX instead of XXX/POLY_XXX for signatures.

    - consolidate signatures
	- e.g., use MONO_DICT for the IntMap structure.

    - Name structure is renamed Atom.
	- removed name_tbl type and operations and define free-standing
	  structures AtomDict and AtomTbl.

    - split Format structure into Format and Scan
	- do we want to use the same fmt datatype for both?

    - move Unix specific modules to Unix library.

    - remove signatures and structures that are redundant with the
      SML Basis Library.

