unify applyfun interface

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/partykit@649 255f4249-2263-4417-b1ea-8498779e27a7
simplify perturb argument in cforest; weights can be a matrix

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/partykit@650 255f4249-2263-4417-b1ea-8498779e27a7