Nettlesome

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- add MANIFEST.in (to display readme on PyPI)

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- replace NumberRange with IntRange and FloatRange
- replace Marshmallow serializers with Pydantic
- Entity and Predicate models don't allow extra fields
- add equal sign as default value for QuantityRange sign
- fix bug: bool(Term) returned False if the Term's "length" was 0
- remove custom reprs that can be replaced by Pydantic BaseModel repr

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- internally_consistent raises ValueError identifying contradiction

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- change Doctrine class name to Assertion
- change Predicate param name from template to content
- add Marshmallow schemas
- add APISpec for documenting Marshmallow schemas

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- Fact constructor accepts truth param
- allow alternate methods to specify context for .implies()
- add string expansion to ContextRegister.from_lists
- all Explanation.from_context calls expand strings
- disallow repeated Terms in TermSequence
- fix bug: _context_registers method yielded same ContextRegister repeatedly
- add DuplicateTermError
- fix bug: FactorGroup.union used duplicative TermSequence
- ContextRegister.from_lists works with unequal length lists
- add contradicts_same_context method
- add repr method for subclasses of Comparable to inherit

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- add FactorMatch NamedTuples to be listed in Explanation
- remove FactorGroup.comparison method. Instead use implies, contradicts, etc.
- Factor "explanations" methods yield Explanation, not ContextRegister
- add FactorGroup.explanations_implied_by method
- fix bug: shares_all_factors passed without checking all factors
- fix bug: two empty FactorGroups should have same meaning