0.9.0

• Mixture of Experts improvements: (#282 thanks @jbussemaker, #283)
  • add variance prediction API (ie. predict_variances()) which is enabled when variances_support option is set
  • add MOESurrogateModel class which adapts MOE to the SurrogateModel interface
  • allow selection of experts to be part of the mixture (see allow/deny options)
  • MOE.AVAILABLE_EXPERTS lists all possible experts
  • enabled_experts property of an MOE instance lists possible experts wrt derivatives/variances_support
    and allow/deny options.
• Sampling Method interface refactoring: (#284 thanks @LDAP)
  • create an intermediate ScaledSamplingMethod class to be the base class for sampling methods
    which generate samples in the [0, 1] hypercube
  • allow future implementation of sampling methods generating samples direcly in the input space (i.e. within xlimits)
• Use of Gower distance in kriging based mixed integer surrogate: (#289 thanks @raul-rufato )
  • add use_gower_distance option to MixedIntegerSurrogate
  • add gower correlation model to kriging based surrogate
  • see MixedInteger notebook for usage
• Improve kriging based surrogates with multistart method (#293 thanks @Paul-Saves )
  • run several hyperparameter optimizations taking the best result
  • number of optimization is controlled by n_start new option (default 10)
• Update documentation for MOE and SamplingMethod (#285)
• Fixes (#279, #281)