Included Eric Zivot as ctb, incremented version, adjusted date


git-svn-id: svn://svn.r-forge.r-project.org/svnroot/urca@58 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Included import for nlme


git-svn-id: svn://svn.r-forge.r-project.org/svnroot/urca@59 edb9625f-4e0d-4859-8d74-9fd3b1da38cb