Nettlesome

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- fix: non-generic Entities with different names don't have same meaning

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- fix bug: multiple UnitRegistries conflicted
- fix bug: Comparison.implies(Predicate) should be False
- merge "comparable" module into "terms" module
- fix bug: Comparison >= Predicate should be False

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- create UnitRange, DateRange, and NumberRange classes

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- fix bug: Comparable._context_registers could fail when a Factor's terms could be reordered
- add repr method for TermSequence

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- fix scaling of numbers in FiniteSet when comparing with different physical units

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- Migrate semantic reasoning features from AuthoritySpoke