The **Util Library** has code that is over 30 years old and many of the interfaces
could do with a redesign.  Since such a change would break lots of existing code,
we will instead create a new library called the **SML/NJ Util Library** with
CM file `smlnj-util-lib.cm`.  This file contains notes about things that should be
fixed/changed in that redesign.

The HASH_KEY and ORD_KEY signatures should be changed to match newer conventions.

The MONO_ARRAY_SORT should have a fixed comparison function and should also
contain the Binary Search function from the `BSearchFn` functor.

Eliminate currying from the hash-table modules

Eliminate the SplayTree and BinaryTree implementations of maps and sets; the
RedBlackTree implementation is more performant across the board.  We'll keep
the sorted-list based versions too for a lightweight implementation.

The logical bit-sequence operations in BitArray need rethinking.  Specifically
w.r.t. padding lengths.

