=> vignette: kontinuierliche parametrization
=> portfolio optimization: vignette and examples
=> doc: step.aic.ghyp k==2 beschreiben
=> q/p.default: nur einmal warnen
=> Student-t: wenn dof >= z.B. 1e5 mit gauss arbeiten
=> cauchy in student.t (modify construcor).
=> vignette: stable property of NIG.
=> fit.ghypuv/mv crahses if symmetric is named!
=> transform(ghyp.ab(), ...) returns "chi.psi" parametrization
=> fit.ghypmv: EM has closed form for NIG distribution
=> 'ghyp.moment' crashes if Gaussian object is submitted.
