add release notes for ability to specify prior proposal and rejection strategy
* `Keanu.Sampling.SimulatedAnnealing`
* `Keanu.Sampling.MCMC` (to automatically choose between `MetropolisHastings` and `NUTS`)
* The `PosteriorSamplingAlgorithm` objects are now immutable: you cannot set their values after construction.
+* When you choose a custom configuration of `MetropolisHastings` or `SimulatedAnnealing`, you can specify:
+ * the proposal distribution. Options are `PriorProposalDistribution` and `GaussianProposalDistribution`
+ * a proposal rejection strategy - options are `RollBackToCachedValuesOnRejection` and `RollbackAndCascadeOnRejection`
+ * (in Python, this is done for you)
* `Hamiltonian` Monte Carlo has been removed: use `NUTS` instead which is an auto-tuning implementation of Hamiltonian Monte Carlo.
* The `PosteriorSamplingAlgorithm` and `FitnessFunction` interfaces requires a `ProbabilisticModel` as its argument instead of a `BayesianNetwork`
* You can create a `ProbabilisticModel` from a `BayesianNetwork`:
