new argument refitSmoothOffset in validateFDboost() to replicate results of cvrisk() 
+ allow to specify an offset for all values in FDboost() for irregular data

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/fdboost@81 edb9625f-4e0d-4859-8d74-9fd3b1da38cb