-Use RcppEigen
-add probability function
-update doc

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/rankclust@34 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
delete inst and eigen

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/rankclust@35 edb9625f-4e0d-4859-8d74-9fd3b1da38cb