(*) submit vignette
(*) R help pages done?
(*) implement coloring in splom2?
(*) which functions in ./tests to export?
(*) put package to CRAN

Outlook:
(*) implement color-feature in splom2 (now that i and j are included by Deepayan)
(*) allow families to have outer power parameters (outer power families)
(*) incorporate the limits theta=0 for Frank and Clayton
(*) maybe add a slot "survival = FALSE" that returns (if TRUE) 1-U instead
    of U (so that 1-U is following the corresponding survival copula).
(*) maybe add an ASCII-plot for the hierarchical structure;
    Actually, define setAs("nacopula", "dendrogram", ....) and then use
    dendrogram print()ing.
(*) adjust prob() function to allow for larger dimensions (via
    bit-representation... s. paper "Computing the Volume of n-Dimensional
    Copulas", Umberto Cherubinia; Silvia Romagnoli).