- makes it easier to use as a wordHashSet replacement for situations
where we want to avoid duplicates but retain the input order.
- support construction from HashTable, which means it works like the
HashTable::sortedToc but with its own hashing for these keys.
- expose rehash() method for the user. There is normally no need for
using it directly, but also no reason to lock it away as private.
DynamicList
-----------
- construction, assignment and append
HashSet
-------
- construction, insert, set.
- assignment will use the implicit List constructor
hashedWordList
--------------
- construction, assignment
- additional sort() and uniq() methods.
- Readonly access to HashTable information via lookup() method.
- NB: could avoid 'const char**' constructors in the future
