Bug fix: I had forgot to define the iterator for the dictionary type.
Now it is defined and makes use of the new built-in data type "Pair."
Bug fix: 'Dao.HashMap._alter' and 'Dao.HashMap.hashAlter' were
incorrectly defined to ignore empty maps, so inserting objects to empty
'Dao.HashMap.HashMap's would always return an empty
'Dao.HashMap.HashMap'. This has been fixed.
Wrote the 'Dao.interpreter.defIndexer' and
'Dao.Interpreter.defIndexUpdater' methods for the built-in Dao runtime
data type "HashMap".