implement reading List fields

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/rgdal@510 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
implement reading List fields

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/rgdal@511 edb9625f-4e0d-4859-8d74-9fd3b1da38cb