New Features
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* `TruncateComposite` which filters high energy solutions out of the sample set to speed up post-processing
* `BinaryPolynomial` class for representing higher-order problems
* `PolySampler` abstract base class for sampling binary polynomials
* `PolyScaleComposite` binary polynomial version of `ScaleComposite`
* `PolyTruncateComposite` binary polynomial version of
`TruncateComposite`
* `SampleSet.data_vectors` property has been restored
* New serialization for `SampleSet` and `BinaryQuadraticModel` including a bytes serialization for `SampleSet`
* New `DimodJSONDecoder` and `dimod_object_hook`, and refactored `DimodJSONEncoder`
Fixes
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* `SpinReversalTransformComposite` now correctly uses the flipped bqm
* Can now print large samplesets without triggering a recursion error
Deprecated
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* Binary quadratic model sampling in binary polynomial samplers will be removed in 0.9.0
* `SpinReversalTransformComposite` now ignores the `spin_reversal_variables` keyword argument and it will be removed in 0.9.0
* Serialization has been refactored, the bqms and sample sets serialized with the 1.0.0 format are supported until 0.9.0