RcppEnsmallen 0.2.17.0.1

• Upgraded to ensmallen 2.17.0: "Pachis Din Me Pesa Double" (2021-07-06)
  • CheckArbitraryFunctionTypeAPI extended for MOO support
    (mlpack/ensmallen#283).
  • Refactor NSGA2
    (mlpack/ensmallen#263,
    mlpack/ensmallen#304).
  • Add Indicators for Multiobjective optimizers
    (mlpack/ensmallen#285).
  • Make Callback flexible for MultiObjective Optimizers
    (mlpack/ensmallen#289).
  • Add ZDT Test Suite
    (mlpack/ensmallen#273).
  • Add MOEA-D/DE Optimizer
    (mlpack/ensmallen#269).
  • Introduce Policy Methods for MOEA/D-DE
    (mlpack/ensmallen#293).
  • Add Das-Dennis weight initialization method
    (mlpack/ensmallen#295).
  • Add Dirichlet Weight Initialization
    (mlpack/ensmallen#296).
  • Improved installation and compilation instructions
    (mlpack/ensmallen#300).
  • Disable building the tests by default for faster installation
    (mlpack/ensmallen#303).
  • Modify matrix initialisation to take into account
    default element zeroing in Armadillo 10.5
    (mlpack/ensmallen#305).