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Released 2015-03-31, codename "zoom zoom"
- Added ``color`` parameters to lots of interfaces that directly or
indirectly call into echoing. This previously was always
autodetection (with the exception of the ``echo_via_pager``
function). Now you can forcefully enable or disable it, overriding
the auto detection of Click.
- Added an ``UNPROCESSED`` type which does not perform any type
changes which simplifies text handling on 2.x / 3.x in some special
advanced usecases.
- Added ``NoSuchOption`` and ``BadOptionUsage`` exceptions for more
generic handling of errors.
- Added support for handling of unprocessed options which can be
useful in situations where arguments are forwarded to underlying
tools.
- Added ``max_content_width`` parameter to the context which can be
used to change the maximum width of help output. By default Click
will not format content for more than 80 characters width.
- Added support for writing prompts to stderr.
- Fix a bug when showing the default for multiple arguments.
- Added support for custom subclasses to ``option`` and ``argument``.
- Fix bug in ``clear()`` on Windows when colorama is installed.
- Reject ``nargs=-1`` for options properly. Options cannot be
variadic.
- Fixed an issue with bash completion not working properly for
commands with non ASCII characters or dashes.
- Added a way to manually update the progressbar.
- Changed the formatting of missing arguments. Previously the internal
argument name was shown in error messages, now the metavar is shown
if passed. In case an automated metavar is selected, it's stripped
of extra formatting first.