Tornado-problem-details

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- Renamed primary branch to "main"
- Drop Python 2.7 support
- Add type annotations
- Rewrite examples to use asyncio instead of the Tornado IOLoop
- Drop support for older Tornado versions (6.0+ is required now)

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- Make json encoder configurable.
- Add example of using Open API and JSON schema validation together

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- Make content type configurable.

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- Made compatible with Python 2.7, Tornado 4.4, Tornado 4.5, & Tornado 5.

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- Add :exc:`problemdetails.Problem`

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- Initial alpha release containing a very simple implementation.

.. _Next Release: https://github.com/dave-shawley/tornado-problem-details/compare/1.0.0...main
.. _1.0.0: https://github.com/dave-shawley/tornado-problem-details/compare/0.0.6...1.0.0
.. _0.0.6: https://github.com/dave-shawley/tornado-problem-details/compare/0.0.5...0.0.6
.. _0.0.5: https://github.com/dave-shawley/tornado-problem-details/compare/0.0.4...0.0.5
.. _0.0.4: https://github.com/dave-shawley/tornado-problem-details/compare/0.0.2...0.0.4
.. _0.0.2: https://github.com/dave-shawley/tornado-problem-details/compare/0.0.1...0.0.2
.. _0.0.1: https://github.com/dave-shawley/tornado-problem-details/compare/0.0.0...0.0.1