Speed up on how auc() adds missing (0,0) and (1,1).

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/aroma-dots@3586 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
o Now fitRoc() also returns the number of positives and negatives.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/aroma-dots@3587 edb9625f-4e0d-4859-8d74-9fd3b1da38cb