Added more flexibility to class 'Score'; changed arguments of causal inference algorithms

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/pcalg@271 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Merged trunk to dev branch

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/pcalg@272 edb9625f-4e0d-4859-8d74-9fd3b1da38cb