Dimod

* Add new keyword parameter to `BinaryQuadraticModel.to_coo` and `BinaryQuadraticModel.from_coo`

Bug fixes

* bug fixes in Sampler abc. Thank you to kotarotanahashi for the fix
* Add new `to_serializable` and `from_serializable` methods to BinaryQuadraticModel
* Deprecate `to_json`, `from_json`, `to_bson`, `from_bson` methods on BinaryQuadraticModel

* Change the `Response` object API
* Update the embedding chain break methods to be faster
* Add new serialization methods

* Add `BinaryQuadraticModel.to_numpy_vectors` method
* Add `BinaryQuadraticModel.from_numpy_vectors` method

* add new `make_quadratic` function that reduces higher-order polynomials to binary quadratic models.