Wai.common

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- Configuration schema caching is now lazier than ever.
- JSON serialisation now validates in both directions.

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- Fixed bug in Configuration where cached schema were preventing grand-inheritance.

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- Added support for checking Python versions.
- get_argument_to_typevar now works with Python3.6 and Python3.7.

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- Fix so that JSON schema definitions propagate through all composite schema.

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- JSON schema package now has tools for working with references/definitions.
- Configurations now validate additional properties as JSON by default.

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- Added StrictConfiguration, which disables additional properties by default.
- Minor fixes.