Class for the ARFIMA Parameter Distribution, objects of which are created by
calling function arfimadistribution.
dist:Object of class "vector" Details of fitted
parameters.
truecoef:Object of class "matrix" The actual
coefficients.
model:Object of class "list" The model specification.
signature(x = "ARFIMAdistribution"): extracts
various values from object (see note).
signature(object = "ARFIMAdistribution"): parameter
distribution summary.