'ft' tweak + cosmetics

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/coin@856 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
safer

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/coin@857 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
make 'is_integer' try a little bit harder

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/coin@858 edb9625f-4e0d-4859-8d74-9fd3b1da38cb