VITA and IG Simulation for Given Covariance and Marginals

User specifies population covariance matrix. Marginal information may be fully specified, for which the package implements the VITA (VIne-To-Anything) algorithm. Groenneberg and Foldnes (2017) . Alternatively, marginal skewness and kurtosis may be specified, for which the package implements the IG (independent generator) algorithm. Foldnes and Olsson (2016) .