0.8.0

• Noise API changes for Kriging based surrogates (#276, #257 thanks @anfelopera):
  • add a new tutorial notebook on how to deal with noise in SMT
  • rename noise as noise0 option and is now a list of values
  • add option use_het_noise to manage heteroscedastic noise,
  • improve noise management for MFK (different noise by level),
  • add option nugget to enable the handling of numerical instabilitily
  • matern kernel documentation
• Add predict_variance_derivatives API (#256 , #259 thanks @Paul-Saves)
  • add spatial derivatives for Kriging based surrogates
  • fix respect of parameters bounds in Kriging based surrogates
• Notebooks updates (#262, #275 thanks @NatOnera, #277 thanks @Paul-Saves )
  • SMT tutorial
  • SMT EGO tutorial
  • SMT Mixed Integer tutorial
• Kriging based surrogates refactoring (#261 thanks @anfelopera)
  • inheritance changes: MFKPLS -> MFK, KPLSK, GEKPLS -> KPLS
  • improve noise options consistency
  • improve options validity checking
• Code quality (#264, #267, #268 thanks @LDAP):
  • use of abc metaclass to enforce developer API
  • type hinting
  • add 'build system' specification and requirements.txt for tests, setup cleanup