More vdW-DF "name regularization", reinstated check on unknown labels, some
warnings added for backward-compatobility


git-svn-id: http://qeforge.qe-forge.org/svn/q-e/trunk/espresso@11121 c92efa57-630b-4861-b058-cf58834340f0
Maybe better to stop if obsolete XC lables are used


git-svn-id: http://qeforge.qe-forge.org/svn/q-e/trunk/espresso@11122 c92efa57-630b-4861-b058-cf58834340f0
Better explanation of the changes made


git-svn-id: http://qeforge.qe-forge.org/svn/q-e/trunk/espresso@11123 c92efa57-630b-4861-b058-cf58834340f0