Several changes to make psychotree compatible to new psychotools functionality.
- Changed calls/references to new *model functions/help pages
- Integrated new threshpar functions when plotting with node_effects()
- Updated DESCRPTION and NEWS accordingly


git-svn-id: svn://svn.r-forge.r-project.org/svnroot/prefmod@230 edb9625f-4e0d-4859-8d74-9fd3b1da38cb
Removed help pages of node_ccc(), node_rsmplot(), plotCCC.pctree() as these functions never have been released.

git-svn-id: svn://svn.r-forge.r-project.org/svnroot/prefmod@231 edb9625f-4e0d-4859-8d74-9fd3b1da38cb