Density and random generation for Multivariate Skew t-distributions with mean vector mean,
covariance matrix cov, degrees of freedom nu, and skew parameter verctor del.
# NOT RUN {n <- 100
p <- 2
mean <- rep(0,p)
cov <- diag(p)
nu <- 3
del <- c(0,1)
set.seed(3214)
y <- rdmst( n,p,mean,cov,nu,del)
den <- ddmst(y,n,p,mean,cov,nu,del)
# }