Squashed commit of the following:

commit 015e489cd18fe27c5f653d681b3d79c4513ca66c
Author: Emmanuel Rousseaux <emmanuel.rousseaux@gmail.com>
Date:   Mon Nov 17 10:51:42 2014 +0100

    makes Dataset depreciated

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/dataset@154 edb9625f-4e0d-4859-8d74-9fd3b1da38cb