export the "extended" debye[12](x)

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/nacopula@1087 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
add embarrassingly missing "-" (negative sign)


git-svn-id: svn://svn.r-forge.r-project.org/svnroot/nacopula@1088 edb9625f-4e0d-4859-8d74-9fd3b1da38cb