Summary of important user-visible changes for datatypes 1.6.0:
--------------------------------------------------------------

 This release adds the `dictionary` class, a map of unique keys to values,
 with `readdictionary` and `writedictionary` for JSON files, and lets
 `datetime` detect dates in the language of its 'Locale'.

 ** New class `dictionary`: keys of one type mapped to values of one type,
    kept in the order they were added.  Every method of MATLAB's: `insert`,
    `lookup`, `remove`, `entries`, `keys`, `values`, `isKey`, `numEntries`,
    `types` and `isConfigured`, with indexing by `()` and `{}`, comparison
    and hashing.  Keys may be numbers, text, dates, durations, categoricals,
    structures, cell arrays, function handles, `missing` or dictionaries.

 ** New functions `configureDictionary`, `isdictionary` and
    `readdictionary`.  `readdictionary` reads a JSON file or web address
    with MATLAB's options, and the `writedictionary` method writes one.
    Both also read and write a dictionary of tables or timetables as an
    OpenDocument spreadsheet, one sheet per key.  Remote stores and
    archives are not supported.

 ** `datetime` detects text under a 'Locale' as MATLAB does: the locale's
    month names, its long forms (`1. Januar 2024`, `5 de marzo de 2024`),
    dotted dates, and slashed dates in the locale's order, with a time or a
    two-digit year.

 ** `str = disp (x)` returns the printed text for cell arrays and every
    class of the package; for a cell array it used to fail.

 ** `table` and `timetable` refuse a `dictionary`, `timeseries` or
    `tscollection` variable, which a cell variable holds instead.  A
    `timeseries` variable used to be accepted and then misbehave.

 ** Cell display shows function handles, which it showed as `{}`, and the
    imaginary part of complex numbers.

 ** Deliberate deviations from MATLAB are documented in the docstrings of
    the functions they affect.  The ones most likely to be met: a
    `dictionary` takes a table of any size as one value and refuses a key
    type it cannot hash; it reads dates given as text in the time zone of
    its keys; `readdictionary` and `writedictionary` refuse complex values,
    on which MATLAB crashes; `datetime` reads a two-digit year in detected
    text against the pivot year.
