Changes
------------
* Removed `OrderedBinaryQuadraticModel`
* Change the way the `BinaryQuadraticModel` stores the biases to speed up calculations and to save memory
* Deprecated `Response` in favour of `SampleSet`. `Response` is targeted to be removed in 0.9.0 release
* Updated reference samples and composites to use `SampleSet`
* Moved `dimod.io` namespace under `dimod.serialization`
* Removed `dimod.embedding` subpackage, it is now part of [dwave-system](https://github.com/dwavesystems/dwave-system) under `dwave.embedding` namespace.
New Features
-------------------
* `BinaryQuadraticModel.normalize` method, thanks wbernoudy
* `BinaryQuadraticModel.fix_variables` method
* `BinaryQuadraticModel.energies` method
* `SampleSet.to_pandas` method
* `FixedVariableComposite`, thanks conta877
* `poly_energy` and `poly_energies` function for higher order polynomials, thanks conta877
* Parameter to ignore some variables/interactions in `BinaryQuadraticModel.normalize` and `BinaryQuadraticModel.scale` methods, thanks conta877
* Fix broken documentation link, thanks schnorea