- improved as.families: User can now also specify 
  fname as function or evaluated function
- plot_PI now potentially works for all families
- added qfun to (most of the) families which 
  is required for plot_PI
- moved some helper functions to helpers.R
- improvements in manuals


git-svn-id: svn://svn.r-forge.r-project.org/svnroot/gamboostlss@96 edb9625f-4e0d-4859-8d74-9fd3b1da38cb