Function that creates matrices C and M for the marginal parametrization of the probability vector for a vector of categorical variables (internal use)
marg_param(lev, type)vector containing the number of levels of each variable
vector with elements "l", "g", "c", "r" indicating the type of logit
matrix of constrats (the first sum(lev)-length(r) elements are referred to univariate logits)
marginalization matrix with elements 0 and 1
corresponding design matrix for the corresponding log-linear model