hhh4() stores the runtime just like twinstim()

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/surveillance@705 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
nonparametric neighbourhood order weights for hhh4()

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/surveillance@706 edb9625f-4e0d-4859-8d74-9fd3b1da38cb