check factor levels of newdata

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/partykit@423 255f4249-2263-4417-b1ea-8498779e27a7
comments / questions

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/partykit@424 255f4249-2263-4417-b1ea-8498779e27a7