Rcpp implementation of dist.matrix() finished

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/wordspace@73 4e9de6a8-e6b3-4a20-ba07-35caea2ed9df
bug fixes

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/wordspace@74 4e9de6a8-e6b3-4a20-ba07-35caea2ed9df