own tree example with Titanic data set

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/partykit@455 255f4249-2263-4417-b1ea-8498779e27a7
show example tree algorithm

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/partykit@456 255f4249-2263-4417-b1ea-8498779e27a7