Suppress warning in sparseby where factor variables had a string label.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/r2mlwin@239 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Add a previous version of Formula.translate to handle backwards compatibility with models using the old version of the syntax.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/r2mlwin@240 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Remove TODO items that have now been addressed.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/r2mlwin@241 edb9625f-4e0d-4859-8d74-9fd3b1da38cb