implemented a sampling algorithm for FGM copulas in R; Ivan has C code on this, see ?rfgmCopula, however, this uses a different parameterization; not clear if the C code actually works; would be good to agree on a parameterization...

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/nacopula@1079 edb9625f-4e0d-4859-8d74-9fd3b1da38cb