r.squaredGLMM: added conditional R^2 for poisson-log models

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/mumin@257 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
r.squaredGLMM: bugfix, manual updated


git-svn-id: svn://svn.r-forge.r-project.org/svnroot/mumin@258 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
r.squaredGLMM: manual updated
NEWS updated, current packages added


git-svn-id: svn://svn.r-forge.r-project.org/svnroot/mumin@259 edb9625f-4e0d-4859-8d74-9fd3b1da38cb