- stabsel:
  * implemented "unimodal" error bound
  * added new option assumption = c("unimodal", "r-concave", "none")
  * renamed error.bound to sampling.type
- Bugfix: mod$which() returned not all base-learners


git-svn-id: svn://svn.r-forge.r-project.org/svnroot/mboost@762 edb9625f-4e0d-4859-8d74-9fd3b1da38cb